The plates of a parallel plate capacitor of capacitance C0​ are horizontal. Into the gap, a slab of dielectric material with K=2 is placed, filling the bottom half of the gap between the plates. What is the resulting new capacitance?
a. 2/5 ​C0​
b. 4/3 ​C0​
c. 3/4 ​C0​
d. 5/2 ​C0​