The Work $\overrightarrow { \mathbf { F } } _ { sp} \cdot d ~\overrightarrow { { x } }$

The work $\overrightarrow { \mathbf { F } } _ { sp} \cdot d ~\overrightarrow { { x } }$ done by the force exerted by the spring on a mass attached to the end of the spring when the mass has displacement d $\overrightarrow { \mathbf { x } }$ is

A) always negative.
B) always positive.
C) negative half the time,positive the other half of the time.
D) positive more than it is negative.
E) negative more than it is positive.