（10江苏）二次积分 $\int_{0}^{1} d y \int_{1}^{y+1} f(x, y) d x$ 交换积分次序后得
A. $\int_{0}^{1} d x \int_{1}^{x+1} f(x, y) d y$
B. $\int_{1}^{2} d x \int_{0}^{x-1} f(x, y) d y$
C. $\int_{1}^{2} d x \int_{1}^{x-1} f(x, y) d y$
D. $\int_{1}^{2} d x \int_{x-1}^{1} f(x, y) d y$