Why Do Testes Shrink When Male Athletes Take Synthetic Steroid

Multiple Choice

Why do testes shrink when male athletes take synthetic steroid testosterone hormones?

A) Testosterone itself has the direct effect of shrinking the testes.
B) Synthetic chemicals are not the same in action as natural chemicals.
C) The guilt reaction in the brain causes a reverse hormonal action.
D) The pituitary detects high levels of testosterone in the bloodstream and reduces FSH and LH.
E) Scientists have no explanation for this phenomenon that is opposite of expected.