Component of velocity of ball relative to lift are
$u_x=4 \cos 30 ^{\circ}=2 \sqrt 3 m/s$
$u_y=4 \sin 30 ^{\circ}=2 m/s$
and acceleration of ball relative to lift is $a=10+2=12 m/s^2$ in negative y direction acting downwards.
Therefore Time of flight $T=\large\frac{2u_y}{a}$
$\qquad=\large\frac{2 \times 2}{12}$
$\qquad=\large\frac{1}{3}s$
Hence b is the correct answer.