On a smooth inclined plane,a block of mass $M$ is fixed to two rigid supports using two springs,as shown in the figure. If each spring has spring constant $k$,then the period of oscillation of the block is (Neglect the masses of the springs)

• A
  $2 \pi\left(\frac{M}{2 k}\right)^{1 / 2}$
• B
  $2 \pi\left(\frac{2 M}{k}\right)^{1 / 2}$
• C
  $2 \pi\left(\frac{Mg \sin \theta}{2 k}\right)^{1 / 2}$
• D
  $2 \pi\left(\frac{2 Mg}{k}\right)^{1 / 2}$