Answer
a) Diagram is shown below.
b) Static frictional force is changed to Kinetic frictional force.
c) Static frictional force is changed to Kinetic frictional force.
Work Step by Step
a) The free-body diagram shows the box at rest on a inclined plane. The $F_{fr}$ is Static Frictional Force since the box is at rest.
b) If the box were sliding down the plane, the free-body diagram will be unchanged but $F_{fr}$ will be the Kinetic Frictional Force since the box is moving down the plane.
c) If the box were sliding up the plane, the free-body diagram will be unchanged but $F_{fr}$ will be the Kinetic Frictional Force and arrow pointing in the opposite direction since the box is moving up the plane.
