Answer:
D. Thymine is found only in DNA
Step-by-step explanation:
DNA is a long polymer with deoxyriboses and phosphate backbone. Having four different nitrogenous bases: adenine, guanine, cytosine and thymine.
RNA is a polymer with a ribose and phosphate backbone. Four different nitrogenous bases: adenine, guanine, cytosine, and uracil.