Answer:
Dad is not correct, Dad owes Junior a trip to Europe because Junior's acts are consideration.
Step-by-step explanation:
Although it was Junior's obligation to be enough to pass the subjects, Dad made a promise to Junior. Dad promised a trip to Europe if Junior passed the subjects. Because of that promise, Junior studied hard and fulfilled his part of the bargain, though Dad didn't want to fulfill his. Dad is wrong, Junior's actions should be considered as part of the deal Dad proposed. Junior did his part, so Dad should do his.