Form concentric circles around the wire
C is the awnser because c is single replacement
I attached the full question.
We know that for a parallel-plate capacitor the surface charge density is given by the following formula:

Where V is the voltage between the plates and d is separation.
Voltage is by definition:

Voltage is analog to the mechanical work done by the force.
Above formula is correct only If the field is constant, and we can assume that it is since no function has been given.
The charge density would then be:

Please note that elecric permittivity of air is very close to elecric permittivity of vacum, it is common to use them <span>interchangeably</span>.
"Voltage" is the "pressure" that makes electrons want to leave where they are
and head in some direction, if there's conducting material in that direction.
"Current" is the rate at which they all migrate in that direction.
A gravitational force between objects depends on two things- their masses and the distance between them. So the greater the mass and the less distance there is, the more gravitational force and is the mass is less and the distance is great the gravitational force is weak