—Do you know what EU stands for, Tommy?

—Sure.It stands for the European Union，________ European political and economic organization that encourages trade and friendship between ________ countries that are members.

A．an; the

B．a; the

C．the; /

D．an; /

某中学组织七年级学生参观，原计划租用45座客车若干辆，但有15人没有座位；如果租用同样数量的60座客车，则多出一辆，且其余客车恰好坐满．试问：

（1）七年级学生人数是多少？

（2）原计划租用45座客车多少辆？