A single-degree-of-freedom oscillator is subjected to harmonic excitation $F(t) = F_{0}\cos(\omega t)$ as shown in the figure.

The non-zero value of $\omega$, for which the amplitude of the force transmitted to the ground will be $F_{0}$, is

1. $\sqrt{\dfrac{k}{2m}} \\$
2. $\sqrt{\dfrac{k}{m}} \\$
3. $\sqrt{\dfrac{2k}{m}} \\$
4. $2\sqrt{\dfrac{k}{m}}$