A rear side of a truck is open and a box of mass 20 kg is placed on the truck 4 metres away from the open end. \[\mu =0.15\] and\[\text{g }=\text{ 1}0\text{ m}/{{\text{s}}^{\text{2}}}\]. The truck starts from rest with an acceleration of \[\text{2 m}/{{\text{s}}^{\text{2}}}\]on a straight road. The box will fall off the truck when it is at a distance from the starting point equal to

• A.  4 metres         
• B.         8 metres
• C.  16 metres         
• D.         32 metres