Which quantity will change on increasing the separation between the plates of a charged parallel plate capacitor?

Potential difference between the plates of the capacitor

The correct answer is Option (3) → Potential difference between the plates of the capacitor

The potential difference across the capacitor is related to the -

$V=\vec E.\vec d$

where,

E = Electric field

d = distance between plates

$∴V∝d$

V increased as we increase the separation.