The clever boy made a hole in the wall, _____ he could see _____ was going on inside the house. [ ]

A. which; what

B. through which; what

C. through that; what

D. what; that

《保密法》规定，一切国家机关、武装力量、政党、社会团体、企事业单位和公民都有保守（）的义务。

A.党和国家工作秘密

B.国家秘密

C.企业商业秘密