唔該教下我一條MATHS MC題

唔該教下我一條MATHS MC題，要步驟。

The figure shows a parallelogram PQRS. M and N are points on PQ and PS respectively. It is given that PM:MQ=1:4, PN:NS=1:2 and the area of PQRS is 270 cm^2. Find the area of the shaded region.

果個shaded region係(//gram PQRS-△PMN)

answer:
A. 251cm^2
B. 257cm^2
C. 261cm^2
D. 267cm^2