Multiple choice Which among the following is not a nitrogenous base? Adenine Thymine Ribose Guanine Reveal answer Fill a bubble to check yourself C Correct answer Explanation Ribose is an organic compound with formula C5H10O5.It is specifically, a monosaccharide (simple sugar) with linear form H-(C=O)-(CHOH)4-H, which has all the hydroxyl groups on the same side in the Fischer projection.