​The pathway for de novo biosynthesis of purine nucleotides involves the production of inosine monophosphate (IMP) that serves as a precursor for AMP and GMP synthesis. IMP has the base hypoxanthine whose structure is given below:​

If Hypoxanthine were incorporated into Double stranded DNA, which of the following option correctly represents the order of its pairing preference?

Correct option is B

Explanation-

Hypoxanthine is a purine base that is found in inosine, a nucleoside (base + sugar). In DNA, hypoxanthine does not normally occur, but it can appear: As part of inosine in tRNA Or due to deamination of adenine, a process that converts adenine to hypoxanthine.
Inosine monophosphate (IMP) is an intermediate in purine biosynthesis, leading to AMP and GMP.
Base Pairing Rules-
In normal DNA:
Adenine (A) pairs with Thymine (T) — 2 hydrogen bonds.
Guanine (G) pairs with Cytosine (C) — 3 hydrogen bonds.
Hypoxanthine (in inosine) - Structurally similar to guanine, but lacks the amino group at position 2.

The nitrogenous bases with pairing Strength with Hypoxanthine (I) and their reasons-
Cytosine (C) -  Strongest  -  2 stable hydrogen bonds — good shape and polarity match.
Adenine (A)  -  Moderate  -  Forms 2 hydrogen bonds, less stable than with cytosine.
Thymine (T)  -  Weaker    -  One or two weak hydrogen bonds possible.
Guanine (G)  -   Weakest or negligible   - Bad shape match — both are purines; sterically unfavorable.

So, the correct answer is option b - Cytosine > Adenine > Thymine > Guanine.