The correct answer is A. have been
This is a linking verb that provides the aspect of the main verb that is careful. Should is a modal verb.
Number 2 is showing compare and contrast because similar and different are syninyms to compare and cotrast. They are both asking for the same thing.
The answer to your question is B
For most of the cases, writers put rhyming lines at the end of their writing to create some sort of easier flow for the readers.
This will make the end-rhymed lines will become catchy and easier to remember for the readers
hope this helps