B. The meeting was only supposed to be for an hour; however, it ran for nearly 3 hours.
Explanation:
A semicolon is most commonly used to link (in a single sentence) two independent clauses that are closely related in thought. When a semicolon is used to join two or more ideas (parts) in a sentence, those ideas are then given equal position or rank. Use the semicolon if you have two independent clauses <em>connected without a conjunction</em>. Also use the semicolon when you already have commas within a sentence for smaller separations, and you need the semicolon to show bigger separations.
