Hi, Is this correct? Please explain why. Thank you soon much!?

"1", "2" and "3" have four carbon atoms. "4" has five carbon atoms.

So any answer with "4" is wrong, because there is no other diagram with five carbon atoms.

"1" and "2" are identical, so "1 and 2" is wrong.

So by elimination the correct answer is "1 and 3".

("2 and 3" would also be correct, but that wasn't offered as a choice.)

Correct answers would be 1 & 3 and 2 & 3

This is correct.

Rotate 1 or 2 180° about the horizontal plane of the cyclopropane plane, they are “identical”.

As 3 and 4 have the same molecular formula (C₄H₈) but different structures, they are “structural isomers”.

The answer: 3 and 4