某公司董事会根据年龄确定高管团队为三级架构，年龄越大级别越高。最上一级为CEO，4名副总裁直接向CEO汇报，每位副总裁领导一个部门，且手下有3名总监。若CEO今年50岁，且高管团队各人年龄为互不相同的连续自然数。则部门间高管的平均年龄之差最大为多少

A．5.5岁
B．6岁
C．7岁
D．7.5岁

______postgraduate student at______ medical school of Shanghai Fudan University died Tuesday after drinking water allegedly poisoned by his roommate.

A．the;a

B．the;the

C．a;a

D．a;the