I'm really unsure of how to approach this question...
Polystyrene has a very low dielectric constant compared to most other solid materials. Therefore, we predict for a polystyrene slab pushed between the plates of a parallel plate capacitor:
a. that the amount of charges on the plate changes significantly when holding the potential difference between the plates fixed
b. that the potential difference between the plates is significantly reduced when we hold the charges on the plates fixed.
c. that no changes are observed at all
d. that the changes are much smaller than for a slab of most other solid materials
e. that anything we want to happen can happen
Isnt C=q/v
and if the delectric constant is low, then C, C will increase (from air) some amount, less than for other dielectrics.
q=CV so a is not true ("significantly"
V=q/C a is untrue ("significantly')
c is untrue (no changes)
d true
e if you believe in magic.