A Car Heading North Suddenly Collides at an Intersection with a Truck

Multiple Choice

A car heading north suddenly collides at an intersection with a truck of the same mass heading east. If they lock together and travel at 28 m/s at $15 ^ { \circ }$ north of east just after the collision, how fast was the car initially traveling?

A) 7 m/s
B) 28 m/s
C) 11 m/s
D) 14 m/s