73. ZP3 is a mammalian glycoprotein, which is located in the zona pellucida of eggs where it probably serves two functions:
(A) binds to the heads of sperm and prevents the egg from binding an additional spenn.
(B) shuts off the function of DNA polymerase and RNA polymerase.
(C) directs both the slow and fast block to polyspermy.
(D) stimulates the endospenn and initiates RNA synthesis.
(E) stimulates protein synthesis and destroys the arcosome.