An elevator car whose floor to ceiling distance is 2.7 m starts ascending with constant acceleration of $1.2 m/s^2$ after 2 seconds of the start a bolt begins falling from ceiling of elevator. What is the time after which the bolt hits the floor of the elevator.

Question

$$(a)\;0.8 s\quad (b)\;0.7 s \quad (c)\;0.6s \quad (d)\;0.5 s$$