Problem

A 3kg box on a frictionless table is connected to another hanging 5kg black circular mass via a massless string and a frictionless pulley as seen below.
After the 3kg mass and the 5kg mass are released from rest, they move with constant acceleration. It takes 0.808 seconds for the hanging 5kg black mass to fall 2m and hit the floor. After the 5kg mass hits the floor the string goes slack and no longer exerts any force on either mass.
What is the magnitude of the acceleration of the 3kg box while it moves through the first 2m of motion?
Please choose from one of the following options.