设 $M=\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}} \frac{(1+x)^2}{1+x^2} \mathrm{~d} x, N=\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}} \frac{1+x}{\mathrm{e}^x} \mathrm{~d} x, K=\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}}(1+\sqrt{\cos x}) \mathrm{d} x$, 则
A
$M>N>K$.
B
$M>K>N$.
C
$K>M>N$.
D
$K>N>M$.
E
F