设 $M=\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}} \frac{\sin x}{1+x^{2}} \cos ^{4} x \mathrm{~d} x, N=\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}}\left(\sin ^{3} x+\cos ^{4} x\right) \mathrm{d} x, P=\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}}\left(x^{2} \sin ^{3} x-\cos ^{4} x\right) \mathrm{d} x$, 则有
A
$N < P < M$.
B
$M < P < N$.
C
$N < M < P$.
D
$P < M < N$.
E
F