A. had occurred B. occurred

C. have occurred D. was occurred

【答案】B

【解析】考查动词时态。我今天早上醒来时想到了一个绝妙的主意。短语occur to sb.表示“（想法、念头等）想起、浮现”的意思。句子用一般过去时态，故答案为Ｂ。