Answer: B. Yes, because he kept the car for six months after reaching the age of majority.
Step-by-step explanation:
When the teenager had not reached the age of majority, holding him liable for the contract would have been challenging. The teenager however reached the age of majority he became legally liable for decisions and contracts.
After this age, he had the car for 6 more months which means that he had accepted the contract as an adult. He cannot therefore simply wiggle out of the payment because he signed an enforceable contract.