The correct answer is $\boxed{\text{(C) citric acid}}$.
A tribasic acid is an acid that has three hydrogen atoms that can be ionized in water. Citric acid is a tricarboxylic acid, which means it has three carboxyl groups (-COOH). When citric acid is dissolved in water, the carboxyl groups can lose a hydrogen ion each, forming three citrate ions.
Succinic acid is a dicarboxylic acid, which means it has two carboxyl groups. When succinic acid is dissolved in water, the carboxyl groups can lose a hydrogen ion each, forming two succinate ions.
Lactic acid is a monocarboxylic acid, which means it has one carboxyl group. When lactic acid is dissolved in water, the carboxyl group can lose a hydrogen ion, forming a lactate ion.
Valeric acid is a monocarboxylic acid, which means it has one carboxyl group. When valeric acid is dissolved in water, the carboxyl group can lose a hydrogen ion, forming a valerate ion.