Final answer:
A comma splice is present in the sentence 'O Mary had a dog, his name was Sam.' To correct it, the comma can be replaced with a semicolon or period.
Step-by-step explanation:
The sentence that has a comma splice that needs to be corrected is: O Mary had a dog, his name was Sam.
A comma splice occurs when two independent clauses are joined by a comma without any conjunction to link them. To correct the comma splice in this sentence, we can add a conjunction like 'and' or 'but' or replace the comma with a semicolon or period.
Here's the corrected sentence: O Mary had a dog; his name was Sam.
Learn more about Comma splices in English sentences