"조아요" is correct. We usually don't sound 'ㅎ' when the 'ㅎ' is located below (I mean "받침") and the 'o' follows it. e.g. 않아요 - 아나요 괜찮아요 - 괜차나요 많아요 - 마나요 But when you say "좋다", it sounds like "조타" e.g. 많다 - 만타 괜찮다 - 괜찬타