He ______be being criticized by Mr. Chen, because he keeps his h

He ______be being criticized by Mr. Chen, because he keeps his head down.
A、must
B、can
C、may
D、shall
【正确答案】：A
【题目解析】：Must表示推测，意为“准是”“一定是”。对现在正在进行的情况作出推测时，后接进行式。