A Standard Atmosphere Has a Pressure Versus Altitude Relation Approximated

A standard atmosphere has a pressure versus altitude relation approximated by
? = P_oe-?h_,
With ? = 0.116 km^-1. An aircraft flies at 30,000 ft but maintains a cabin pressure of that at
8000 ft. What force is exerted by air pressure on a square meter of cabin wall area?

A) 4.1 × 10⁴ N
B) 124 N
C) 3.5 × 10⁴ N
D) 7.6 × 10⁴ N