The value of the gravitational field strength of the Earth at a distance R (where R is the radius of the Earth) from the surface of the Earth will be:

(A) 5 Nkg^-1
(B) 10 Nkg^-1
(C) 25 Nkg^-1
(D) 1.1 Nkg^-1

Answer: (C) 25 Nkg^-1