spend The chief executive officer was unwilling to spend his

恕我直言,你学得太教条了,spend in doing sth,和spend on sth是没错,但是也还有其它形式的用法：spend some time on doing sth,意思是花时间做某事,总的来说,spend是那种后面只能跟动名词或名词的动词,所以肯定不选B和D,如果选A,变成：preparation a detailed advertisement presentation.完全不合语法,由题意可知on后面要接一个动名词短语,表示做某事,只能选C.