In experiment in vivo it is fixed a moment in which spermatozoa surround oocyte and corona radiate disappears. What is the name of this process?

In experiment in vivo it is fixed a moment in which spermatozoa surround oocyte and corona radiate disappears. What is the name of this process?

1.  Penetration


2.  Acrosomal reaction


3.  Cortical reaction


4.  Chemotaxis


5.  *Denudation