$v_x =\large\frac{dx}{dy}$$=24 \cos 6t$

$v_y =\large\frac{dy}{dt}$$=24 \sin 6t$

$v=\sqrt {{v_x}^2+{v_y}^2}$

$\quad=24 m/s^2$

Since $v$- speed is constant.

distance traversed in 4 second is

$s=v \times t$

$s=24 \times 4$

$s=96 m$

Hence a is the correct answer.