Select the correct option:

Identify the given structural formulae and select the correct option.

A nucleotide is composed of nitrogenous bases, sugar and phosphoric acid. There is two type of bases which are there in the nucleic acid i.e purines and pyrimidines. Purines have 9 member double ring and nitrogenous bases which possess nitrogen at 1', 3', 7' and 9' position and are known as adenine and guanine. Pyrimidine bases are those that contain nitrogen at 1' and 3' position and are cytosine, thymine, and uracil.