In a $\Delta PQR$, if $ 3 \sin P + 4 \cos Q = 6 $ and $4 \sin Q + 3 \cos P = 1$, then the angle R is equal to

Question

( A ) $\frac{\pi}{6}$
( B ) $\frac{3 \pi}{6}$
( C ) $\frac{5 \pi}{6}$
( D ) $\frac{\pi}{4}$