Based off the process of elimination the answer is C.
A: Francis had a lot on his mind that afternoon, he was concerned about his mother's illness and about losing his job.
After the word Afternoon, there should be a semi-colon rather than a comma.
B: The packing instructions asked each camper to bring the following items, a flashlight, a sleeping bag, sunscreen, and a book for
Independent reading.
After the word items, there should be a colon rather than a comma.
D: The king ordered that all his subjects should show their allegiance through common forms of attire: yet many people continue to wear the traditional hats of their various regions.
After the word attire, there is a colon, when there should be a comma.
Therefore, the answer is C