A boy standing on a weighing machine observe his weight to be $200 N$. when he suddenly jumps upwards, his friend notice that the reading increased to $400 N$. The acceleration with which the boy jumped will be

Question

$$(a)\;9.8 m/s^2\quad (b)\;29.4 m/s ^2 \quad (c)\;4.9 m/s^2 \quad(d)\;14.7 m/s ^2$$