Given below are two statements. One is labeled Assertion (A) and the other is labeled Reason (R).

Assertion (A): If different planets have the same density but different radii, then the gravitational field (g) on the surface of the planet is directly proportional to the radius of the planet.

Reason (R): Intensity of gravitational field is defined as the work done in moving a unit mass from infinity to a point in the field

In light of the above statements, choose the correct answer from the options given below.