A.  

are always living on the same address, because the blockchain is deterministic. So, one account can always have one smart contract.

B.  

are having the same address as the EOA.

C.  

are sitting on their own address. The Address is created from the nonce and the EOA address and could be known in advance before deploying the smart contract.

D.  

the address of the smart contract is a random address which gets generated by the miner who mines the contract-creation transaction.

A.  

True, but it's still good to use Ganache, or even a real private network for testing.

B.  

False, it's necessary to use Ganache or even a real private network for testing.

A.  

to contribute to the box community which is the distributed file system for truffle.

B.  

to start with a pre-configured environment for most web-development needs.

C.  

to use tools that makes boxing of Dapps for different platforms very easy.

A.  

to Wei, so it will send the equivalent of 10^18 Wei.

B.  

to Finney, so it will send the equivalent of 10^3 Finney.

C.  

to Szabo, so it will send the equivalent of 10^6 Szabo.

A.  

you can incorporate inline-assembly to get better controls.

B.  

you have to import pre-compiled assembly files which are then hard-copied into the bytecode of the compiled solidity file.

C.  

you can use Viper, the experimental assembly like language specifically to offer more flexibility.

A.  

a fallback function must be declared and it must be made payable. If there is no fallback function or the fallback function is not payable it will throw an exception.

B.  

either a fallback function which is payable exists, or no fallback function at all exists.

C.  

you cannot send ether to a contract without explicitly calling a function. The fallback function can never receive ether.

A.  

to run tests quickly and especially for free, compared to continuous deployment on the MainNetwork. This way you save a lot of fees, time and costs.

B.  

to run tests in an environment where logging is activated. On the Main-Net you have no access to transaction logs and this is ultimately the information you need to debug your contracts.

C.  

to avoid regression bugs with contracts that are updated constantly on the main-net. Once you update a contract on the main-net, the address stays the same, but the code changes and this can have disastrous side-effects.

A.  

only via JavaScript because there is the proprietary Web3.js library.

B.  

by any programming language, as long as it adheres to the JSON-RPC standard.

A.  

It helps you to find bugs, regression bugs and sometimes also helps you to understand your code from different angles.

B.  

It is a great way to spend time on something that you get paid for. But ultimately it will just slow down the development process.

A.  

works across all compilers and platforms the same way.

B.  

is generally possible, but currently works only in Remix, but doesn't work in Truffle.

A.  

it’s good to use a push over a pull method.

B.  

it’s good to use a push and a pull method to ensure that participants can get their money no matter the contract state. In addition to and pushing it should contain a withdraw method.

C.  

it's good to use only pull and no push method.

A.  

you should capitalize function names, events and contract names, to avoid confusion with JavaScript. You should use Tabs to indentation and a maximum of 80 characters per line.

B.  

contract names should be capitalized, while functions should be mixedCase. You should use 4 spaces as indentation and a maximum of 79 (or 99) characters per line.

C.  

contract should be mixedCase, as well as function names. Events should be capitalized. 2 spaces should be used as indentation and a maximum of 120 characters per line.

A.  

it would be best to start from scratch, just looking at the required interface.

B.  

it is beneficial to copy and paste the already existing code from the Ethereum wiki and modify this until you like it.

C.  

best is to start with an audited implementation, for example from OpenZeppelin, in order to reuse already existing code.

A.  

all gas is consumed

B.  

all remaining gas is returned.

A.  

the Keys can be anything, but the value can't be another mapping or struct.

B.  

the Value can be anything, but the key cannot be another mapping, struct, integer or Boolean.

C.  

the value can be anything, but the key cannot be another mapping, struct, enum or dynamically sized array.