The figure shows an Aluminium rod of 25 mm$$^2$$ cross sectional area. It is loaded at four points, K, L, M and N. Assume E = 67 GPa for Aluminium. The total change in length of the rod due to loading as shown is close to

A

$$30 \mu m$$

B

$$-10 \mu m$$

C

$$-30 \mu m$$

D

$$10 \mu m$$