请教刘振民E8-26

The auto industry has experienced one of its most significant trends in the last 50years, which is the migration of motorists from passenger cars to minivans, sport utility vehicles, and pickups.

(A) The auto industry has experienced one of its most significant trends in the last 50years, which is

(B) Of the trends the auto industry experienced in teh last 50 years has been one of the most significant,

(C) In the last 50 years, one of the most significant trends that the auto industry has been experiencing has been

(D) One of the most significant trends that the auto industry has experienced in the last 50 years is

(E) In the last 50 years , the auto industry experienced one of the most significant trends that it has had, that of

答案是D, 不过解释的不大能看懂

说：在主谓一致中，one of+ 复数名词之后的定语从句的先行词是复数名词，因而A中which和is中主谓不一致。

我不能明白的是：D中用的也是单数，和他给的解释好像也矛盾。

请大家指教，谢谢