Which sentence contains a comma splice?

Question

Marco rode to school on his bicycle this morning, he arrived an hour early.
Marco, who enjoys riding his bicycle to school, arrived just before the bell today.
Marco rode to school on his bicycle on Monday, Tuesday, and Wednesday.
Marco, who rode to school on his bicycle this morning, arrived an hour early.

Answer 1

The sentence that contains a comma splice is:

"Marco rode to school on his bicycle this morning, he arrived an hour early."

A comma splice occurs when two independent clauses are joined by just a comma without a coordinating conjunction. In this case, "Marco rode to school on his bicycle this morning" and "he arrived an hour early" are both independent clauses.