What are the four nitrogenous bases found in RNA? a. cytosine, guanine, thymine, uracil (C, G, T, U) b. adenine, cytosine, guanine, thymine (A, C, G, T) c. adenine, cytosine, guanine, uracil (A, C, G, U) d. alanine, cysteine, glycine, threonine (A, C, G, T)