Two Blocks Connected by a String Are Pulled Across a Horizontal

Two blocks connected by a string are pulled across a horizontal surface by a force applied to one of the blocks,as shown.The coefficient of kinetic friction between the blocks and the surface is 0.25.If each block has an acceleration of 2.0 m/s² to the right,what is the magnitude F of the applied force?

A) 25 N
B) 18 N
C) 11 N
D) 14 N
E) 7.0 N