A bullet of mass 10g id fired horizontally with a velocity $1000 ms^{-1}$ from a rifle situated at a height 50 m above the ground. If the bullet reaches the ground with a velocity $500 ms^{-1}$, the work done against air resistance in the trajectory of the bullet is : $(g=10\;ms^{-2})$

Question

$$\begin {array} {1 1} (a)\;5005\;J & \quad (b)\;3755\;J \\ (c)\;3750\;J & \quad (d)\;17.5\;J \end {array}$$