An Airplane Moves at 120 M/sec to the West with Respect

Multiple Choice

An airplane moves at 120 m/sec to the west with respect to the air.The air moves at 50 m/sec to the south with respect to the ground.How fast does the airplane move with respect to the ground?

A) 70 m/s
B) 120 m/s
C) 130 m/s
D) 170 m/s