A. The net force is acting in an upward direction.

B.
The net force is acting to the left.

C.
The net force is moving to the right.

D.
The net force is zero and all the forces are balanced.

The question is incomplete. complete question is attached belowanswer: correct answer is option b  i.e.  solid particles  reason: filter paper has small pores, through which smaller particles can pass through. however, solid particles  have relatively larger size. hence, they are least likely to pass through.