Now, as, the range of weak nuclear forces is of order
10−18, whereas the range of strong nuclear forces are of order
10−15 i.e. much greater than weak nuclear forces.
Therefore, option (c) is correct.
As we know that,
Electromagnetic forces are long range forces.
Therefore, option (a) will be incorrect.
And since, the relative strength of gravitational forces are order of
10−41 and that of weak nuclear forces are of order
10−6 i.e. every forces are much greater than that of gravitational force.
Hence, option (b) is also incorrect.
And as the relative strength of electromagnetic force is
times that of strong nuclear forces. Hence, option (d) will always be incorrect.