Which one of the following enzymes acts as molecular scissors?

Restriction enzymes

The correct answer is Option (3) → Restriction enzymes 

Restriction Endonucleases (Molecular Scissors): These are enzymes that are commonly referred to as "molecular scissors" because they cut DNA molecules at specific recognition sequences. These recognition sequences are often palindromic, meaning the sequence reads the same forwards and backward.

Restriction enzymes belong to a larger class of enzymes called nucleases. These are of two kinds; exonucleases and endonucleases. Exonucleases remove nucleotides from the ends of the DNA whereas, endonucleases make cuts at specific positions within the DNA.