Identify the given structural formulae and select the correct option.

Options

A. `{:(" A",," B"),("Adenine",,"Uracil"):}`
B. `{:(" A",," B"),("Guanine",,"Thymine"):}`
C. `{:(" A",," B"),("Adenine",,"Guanine"):}`
D. `{:(" A",," B"),("Cytosine",,"Thymine"):}`

Answer

A

Explanation

Nitrogen bases are heterocyclic compounds. They are of two types, substituted purines and substituted pyrimidines. Purines are larger-sized nitrogen containing biomolecules. They have `9-`membered double rings. A purine has imidazole ring joined to pyrimidine ring at `4` and `5` positions. It has nitrogens at 1, 3, 7 and 9 positions. There are two types of purines- adenine (A) and guanine (G). Pyrimidines are `6-` membered rings. A pyrimidine ring has nitrogen at `1` and `3` positions. Pyrimidine bases are of three types-cytosine (C), thymine (T) and uracil (U).