Inside a box there are six smaller boxes,and inside each small box are six much smaller boxes.

How many boxes altogether?    [ ]

A. Thirty-six.  

B. Thirty-seven.

C. Forty-three.

D. Forty-two.

下列哪项是确定现阶段慢性病防治工作优先项目的原则

A．社会负担重的疾病
B．政治影响大的疾病
C．A+B
D．有效防治手段的疾病
E．A+B+D