Two blocks of masses \( M_{1} \) and \( M_{2} \) are connected to e...

Two blocks of masses \( M_{1} \) and \( M_{2} \) are connected to each other through a light spring as shown in figure. If we push mass \( M_{1} \) with force \( F \) and cause acceleration \( a_{1} \) in right direction. What will be the magnitude of acceleration in \( \mathrm{M}_{2} \) ?
(A) \( \mathrm{F} / \mathrm{M}_{2} \)
(B) \( F /\left(M_{1}+M_{2}\right) \)
(C) \( a_{1} \)
(D) \( \left(\mathrm{F}-\mathrm{M}_{1} \mathrm{a}_{1}\right) / \mathrm{M}_{2} \)