You discover a new hormone, designated HAYAT (HYT) hormone, that causes orange plants to flower. To study the HYT signal transduction pathway, you identify mutations that affect the ability of orange plants to flower. Which of the following mutations are single genes affecting orange plant flowering?
a) O, R, A, N, G
b) o, r, a, n, g
c) O, R, A, N, G²
d) o², r², a², n², g²