He ________ that they needed more time to finish the project, and I was finally convinced and allowed them another two months．
A.saidB.explainedC.arguedD.asked在线课程C
解析：
根据题意可知，“我”被说服了，说明“他”就此事是和我“争辩”了，而不仅仅是说(say)了一声。如果是解释(explain)，则应用why引导宾语从句，因为需要解释的是理由。