In the reaction of an acid with water, a hydronium ion forms
select one:
a. that consists of a hydrogen ion covalently bonded to water.
b. by a process known as ionization.
c. that consists of a hydrogen ion bonded to an hydroxide ion.
d. by simple ionic dissociation.

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

Organisms are more likely to be more preserved in mud than sand because mud is moist and wet, while sand is very dry.