The type of coiling in DNA is

The correct option is Right-handed.

To understand why this is the correct answer, let us look at the structural features of DNA:
1. Double Helix Structure: The classic Watson-Crick model of DNA (specifically B-DNA, which is the most common form found in living cells) consists of two polynucleotide chains running in opposite directions, wound around a central axis to form a double helix.
2. Direction of Coiling: When you trace the path of the sugar-phosphate backbones, they spiral upwards in a clockwise direction. This helical twist is referred to as "right-handed" coiling (similar to the threads of a standard screw). If you look down the longitudinal axis of the helix, the chains turn away from you in a clockwise manner.
3. Alternative Forms: While B-DNA is right-handed, there is an alternative form of DNA called Z-DNA that exhibits left-handed, zig-zag coiling. However, the standard, default type of coiling representative of DNA is the right-handed B-DNA form.