18、单选下列积分的敛散性说法错误的是 () ,-|||-(4分)-|||-A (int )_(0)^1dfrac (dx)(1-{x)^4} 发散-|||-B (int )_(0)^1dfrac (dx)(xsqrt {1-x)} 发散-|||-C (int )_(0)^1dfrac (dx)(sqrt {1-{x)^2}} 发散-|||-D (int )_(0)^1dfrac (dx)({x)^2sqrt (1-x)} 发散