Which sentences use commas to join independent clauses? Select the two that apply.

It was almost the end of summer, and Tim wondered if he was scheduled for enough hours that week. Despite the countless hours he had put in as a server at the local diner, he felt all the work may have been useless. He had been hoping to buy a car at the end of the month. He was determined to get that money, and he decided it was time to confront his supervisor.