The correct answer of this question is : C i.e Gravitational < Weak nuclear force < Electromagnetic force < Strong nuclear force.
EXPLANATION:
There are four fundamental forces in nature which are known as gravitational force, weak nuclear force, electromagnetic force and strong nuclear force.
Out of these four fundamental forces, the gravitational force is the weakest forces in nature,but has infinite range.
Weak nuclear force is produced due to W/Z bosons. Hence, it is stronger than gravitational force but weaker as compared to electromagnetic and strong nuclear force. It is a short range force.
Electromagnetic force is the third one which is weaker as compared to strong nuclear force but has infinite range.
Strong nuclear force is a short range, spin dependent strong attractive force that arises between nucleons due to exchange of mesons.