Answer: A. Gregor wishes he himself could have used the money to pay off his parents' debt faster but is happy his family has the money.
Explanation: In "The Metamorphosis" by Franz Kafka, Gregor's reaction to hearing that his father has some money left over from his failed business is He wishes he himself could have used the money to pay off his parents' debt but is happy his family has the money. His father has made a small fortune because he has not touched the money from his failed business which has grown because of interests. He has also been saving from the money that Gregor brought every month.