Q: Fact 1: Testosterone stimulates the reproductive organs to develop into male organs. Fact 2: Male mammals have a tube-like organ called the 'penis'. Given the two facts above, what causes the penis to develop?

pick from the following.
a). Creatine
b). Energy
c). Estrogen
d). Testicles
e). matter vibrating
f). Testosterone
g). movement
h). It expands
A:
f).