A 10-Kg Block on a Rough Horizontal Surface Is Attached

A 10-kg block on a rough horizontal surface is attached to a light spring (force constant = 1.4 kN/m) . The block is pulled 8.0 cm to the right from its equilibrium position and released from rest. The frictional force between the block and surface has a magnitude of 30 N. What is the kinetic energy of the block as it passes through its equilibrium position?

A) 4.5 J
B) 2.1 J
C) 6.9 J
D) 6.6 J
E) 4.9 J