In Studies of Leaf Senescence, When an Excised Leaf Containing

In studies of leaf senescence, when an excised leaf containing radioactive amino acids is spotted with a kinetin-containing solution, the spot:

A) turns yellow and becomes nonradioactive.
B) turns yellow and becomes more radioactive.
C) remains green and becomes nonradioactive.
D) remains green and becomes more radioactive.
E) turns brown and becomes nonradioactive.