Assertion: Five charges `+q` each are placed at Five vertices of a regular pentagon. A sixth charge `-Q`, is placed at the centre of pentagon, then net electrostatic force on `-Q`, is zero.
Reason: Net electrostatic potential at the centre is zero.
Options:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false and R is also false.