The effect of the mass of the spring is accounted for by adding X times its value to the mass, where X is

Question

While calculating the natural frequency of a spring-mass system, the effect of the mass of the spring is accounted for by adding X times its value to the mass, where X is

                                                     

(a)$\frac{1}{2}$                               (b) $\frac{1}{3}$

(c) $\frac{1}{4}$                             (d) $\frac{3}{4}$​​​​​​​