25. The book ______forty maps, ______three of Great Britain.

A．contains; includes

B．is containing; including

C．includes; contains

D．contains; including

设C是四分之一圆域：x²+y²≤1，x≥0，y≥0，用极坐标计算二重积分sin(x²+y²)dxdy，其值是（）。

A．A

B．B

C．C

D．D