Sorry for my being so late but you couldn’t figure out great difficulty I had finding th

问题补充：

Sorry for my being so late, but you couldn’t figure out great difficulty I had finding the right way here.

A. which

B. how

C. what

D. so

答案：

A. which

B. how

(答案→)C. what

D. so

解析：通过分析句子结构，可知这是个复合句，其中包含一个宾语从句，且引导词在从句中作宾语，表示“什么”的意思，故用what。