Determine the elastic potential energy stored in each spring shown...

Options

1. AEnergies: $\dfrac{M^2 g^2}{k_1}$, $\dfrac{M^2 g^2}{k_2}$ and $\dfrac{M^2 g^2}{k_3}$; Time period: $2\pi \sqrt{M \left( \dfrac{1}{k_1} + \dfrac{1}{k_2} + \dfrac{1}{k_3} \right)}
2. BEnergies: $\dfrac{M g^2}{2 k_1}$, $\dfrac{M g^2}{2 k_2}$ and $\dfrac{M g^2}{2 k_3}$; Time period: $2\pi \sqrt{M (k_1 + k_2 + k_3)}$
3. CEnergies: $\dfrac{M^2 g^2}{2 k_1}$, $\dfrac{M^2 g^2}{2 k_2}$ and $\dfrac{M^2 g^2}{2 k_3}$; Time period: $2\pi \sqrt{\dfrac{M}{k_1 + k_2 + k_3}}$
4. DEnergies: $\dfrac{M^2 g^2}{2 k_1}$, $\dfrac{M^2 g^2}{2 k_2}$ and $\dfrac{M^2 g^2}{2 k_3}$; Time period: $2\pi \sqrt{M \left( \dfrac{1}{k_1} + \dfrac{1}{k_2} + \dfrac{1}{k_3} \right)}