Transactions containing the same data to create the same smart contract are:

A. always having the same signature.

B. having a different signature because of the nonce which changes upon every transaction.

Block Timestamp:

A. the timestamp is based on the time zone of the miner, that is why it changes the difficulty continuously to reflect network latency.

B. the timestamp can't be influenced by a miner and is generally considered safe to be used for randomness on the blockchain.

C. the timestamp can be influenced by a miner to a certain degree but it's always independent from the time-zone.

A Blockchain Node:

A. can never become a mining node.

B. can always become a mining node.

C. can become a mining node, depending if the implementation has the functionality implemented.

To store almost all data in the Ethereum Blockchain:

A. a Linked List with pointers to previous blocks hashes is used.

B. a Merkle Patricia Trie is used.

C. a Radix Trie is used because the Merkle Patricia Trie is too inefficient.

When considering smart contracts and the blockchain it's good:

A. to move all existing logic to the blockchain, so everything runs on the same system. This way it might be more complex, but easier to maintain.

B. to move only those parts to the blockchain that really need the blockchain. This way smart contracts can be easier to read, easier to test and are not so complex.

C. to move those parts to the blockchain that deal with Ether transfers. All other parts can remain in traditional database systems. This way only the value-transfer is on the blockchain.