1. If $A, B$ are two interior angles of an acute $\triangle A B C$, then the point corresponding to the complex number $z=(\cos B-\sin A)+\mathrm{i}(\sin B-\cos A)$ in the complex plane is located in
A. the first quadrant
B. the second quadrant
C. the third quadrant
D. the fourth quadrant
$A+B>\frac{\pi}{2} \Rightarrow A>\frac{\pi}{2}-B \Rightarrow \sin A>\cos B$, similarly, $\sin B>\cos A$.
Thus, the point corresponding to the complex number $z$ in the complex plane is located in the second quadrant, so the answer is $B$.