Adenine pairs with Thymine through how many hydrogens bonds?

The correct answer is Option (1) → 2

In the DNA double helix the bases of the two strands are held together by hydrogen bonds, always a purine opposite a pyrimidine. Adenine pairs with thymine through two hydrogen bonds, while guanine pairs with cytosine through three.

NCERT Extract:
Structure of Polynucleotide Chain – “… (iii) The bases in two strands are paired through hydrogen bond (H-bonds) forming base pairs (bp). Adenine forms two hydrogen bonds with Thymine from opposite strand and vice-versa. Similarly, Guanine is bonded with Cytosine with three H-bonds. As a result, always a purine comes opposite to a pyrimidine. This generates approximately uniform distance between the two strands of the helix (Figure 5.2).”