Really, ionization takes place. It means the acid dissociates in water. Ionization is just a fancy way of saying dissociation. Always think easy.
Definition of IONIZATION: The process describing the dissociation of an acid in water.
If it ionizes or dissociates completely in water, then it shows that hydronium is a STRONG ACID. And if it ionizes partially, that shows hydronium is a WEAK ACID.
So, the answer will be choice B. by a process called ionization