Two bodies of masses m$_1$ (4 kg) and m$_2$ (3 kg) are suspended at the ends of a string of negligible mass passing over a friction-less pulley as shown here.The acceleration of the system is

Question

$$(a)\;4.9 m/s^2 \quad (b)\;2.45 m/s^2 \quad (c)\;9.5 m/s^2 \quad(d)\;1.4 m/s^2$$