Answer: A (Owes nothing)
Explanation:
Donald subscribed to a magazine that gave him two years for a year. Even though after the subscription expired the second year, he was still given the magazine for six months despite the fact that he didn't subscribe, Donald does not owe the national magazine company.
It was not his fault that he was sent magazines after his subscription expired and hence is not liable to pay any amount to the company. It's their loss and mistake and he should not be held responsible for their mistake.