Assuming Negligible Friction, What Spring Constant Would Be Needed by the Spring

Multiple Choice

Assuming negligible friction, what spring constant would be needed by the spring in a "B-B gun" to fire a 10. gram pellet to a height of 100 meters if the spring is initially compressed 10. cm?

A) 2.0 × 10³ N/cm
B) 200. N/m
C) 20. N/cm
D) 20. N/m
E) 2.0 × 10^-3 N/m