The figure below shows a steel rod of $$25 mm^2$$ cross sectional area. It is loaded at four points, Kk, L, M, N. Assume E steel = 200 GPa. The total change in length of the rod due to loading is

A

$$1\mu m$$

B

$$-10\mu m $$

C

$$10\mu m $$

D

$$-20\mu m $$