hi please help with part c! thank you :)

Your answer is partially correct. A slab of copper of thickness b = 2.17 mm is thrust into a parallel-plate capacitor of plate area A = 3.27 cm2 and plate separation d = 3.96 mm, as shown in the figure; the slab is exactly halfway between the plates. (a) What is the capacitance after the slab is introduced? (b) If a charge q = 4.39 UC is maintained on the plates, what is the ratio of the stored energy before to that after the slab is inserted? (c) How much work is done on the slab as it is inserted? (d) Is the slab sucked in or must it be pushed in? Copper (a) Number 1.616731e-12 Units F (b) Number 2.2122905 (c) Number 7.2254975 Units