The diameter of a circle can be found with the formula:

So diameter is two times or twice the radius.
In the given figure, in circle C , the measure of radius KC is 2 inches.
As we know diameter is two multiplied by radius, so we can multiply our radius KC with 2 to get the diameter of circle C.
Plugging the value of radius in the given formula we have,


So the diameter of circle C is 4 inches.
Answer: Diameter is 4 inches for the circle C. Last option 4" is the right choice.