Answer: B. Allocutus

Explanation:
Allocutus is a term used in criminal law, specifically during sentencing, to describe a defendant’s plea for mercy or mitigation. It is not considered a source of Nigerian law. Common law, equity, statutes of general application, and judicial precedence are established sources of Nigerian law. Allocutus is, therefore, the correct answer, as it doesn’t fall under the classification of a law source.