A Box Rests on a Horizontal Surface with One Edge $\times$

A box rests on a horizontal surface with one edge against a small ridge as shown.If the force is 840 N and the bottom right edge of the box is just slightly off the ground,what is the weight of the box? (Hint: With the right edge slightly off the ground,the forces applied by the floor and the ridge must be at the bottom left corner of the box,and the angle can be taken to be negligibly small.)

A) 420 N
B) 590 N
C) 840 N
D) 1.7 $\times$ 10³ N
E) 2.4 $\times$ 10³ N