Which of the following is a run-on sentence/ comma splice?

A. Pablo waited for her slice of pizza to cool, she had already burned the roof of her mouth with the fried cheese sticks.

B. Pablo waited for her slice of pizza to cool. She had already burned the roof of her mouth with the fried cheese sticks.

C. Pablo waited for her slice of pizza to cool because she had already burned the roof of her mouth with the fried cheese sticks.

D. none of the above