I was given three books on cooking, the first ________ I really enjoyed．
A.of thatB.of whichC.thatD.which在线课程B
解析：
此题的大意是：“有人给了我三本有关烹调的书，我很喜欢第一本。”“我很喜欢这三本烹调书的第一本”应表达为：I really enjoyed the first of the three books on cooking．由此可判断出答案应在A和B项中选择。that引导定语从句时，不可以放在介词后面。所以排除A项。