In which sentence is whom used correctly?

Ineed . identify the item that shows sharp and vivid details rather than vague and general ones (put a or b for your answer.) a. my brother doesn’t know the value of money. he buys new things, even though his old ones are still perfectly good. he recently took his girlfriend on a trip. they stayed at a nice hotel and ate all their meals out. while they were there, he proposed marriage to her and gave her an engagement ring. b. my brother bought a new car this year, even though his last car was only three years old and running well. he recently took his girlfriend to hawaii for a week. they stayed at a hilton hotel right on the beach and ate dinner by candlelight in elegant gourmet restaurants. on their last night there, he surprised her with a two-carat diamond ring.