Two springs of force constants k and 2k arc connected to a mass mas shown below :
 

The frequency of oscillation of the mass is :

• A

  $\frac{1}{2\mathrm{\pi }}\sqrt{\frac{\mathrm{k}}{\mathrm{m}}}$

• B

  $\frac{1}{2\mathrm{\pi }}\sqrt{\frac{2\mathrm{k}}{\mathrm{m}}}$

• C

  $\frac{1}{2\mathrm{\pi }}\sqrt{\frac{3\mathrm{k}}{\mathrm{m}}}$

• D

  $\frac{1}{2\mathrm{\pi }}\sqrt{\frac{\mathrm{m}}{\mathrm{k}}}$