What are the steps on solving this?

16.4 The figure shows a block of mass m=5kg moving up an inclined plane of angle 0 = 25 and which is acted on by a horizontal force of magnitude F=80N. If the block has an acceleration directed up the plane of magnitude a=4.2 m/$2, what is the coefficient of kinetic friction /k? (A) 0.3 (B) 0.5 (C) 0.7 (D) 0.4 (E) 0.9