The rear side of a truck is open and a box of 40 kg mass is placed 5 m away from the open end as shown in Figure. The coefficient of friction between the box the surface below it is 0.15. On a straight road the truck starts from rest and accelerates with 2 m s^-2. At what distance from the starting point does the box fall from the truck? (Ignore the size of the box).
 

• A

  20m

• B

  10m

• C

  

• D

  5m