—Who's the man over there? Is it Mr Black?

—It _____ be him. He's much taller. [ ]

A. can't

B. mustn't

C. should

D. may

马克思主义认为人的全面发展的重要前提是( )

A．人的生理特征

B．有目的、有计划的教育

C．自然环境与社会环境

D．社会生产力及其决定的分工状况