What does the strength of an acid or base depend on?

The correct answer to this question is C.

Acids and bases behave differently in a solution based on their strength. Acid or base strength is a measure of how readily the molecule ionizes in water. An acid or base's strength refers to its degree of ionization. A strong acid will completely ionize in water, while a weak acid will only partially ionize. Since there are different degrees of ionization, there are different levels of weakness. When a solute is added to water, a neutral, acidic, or basic solution will arise. The ultimate solution pH will depend on a reaction between the solute and water.