A Light Triangular Plate OAB Is in a Horizontal Plane

Multiple Choice

A light triangular plate OAB is in a horizontal plane.Three forces,F₁ = 6.0 N,F₂ = 9.0 N,and
F₃ = 7.0 N,act on the plate,which is pivoted about a vertical axes through point O.In the figure,
₂ is perpendicular to OB.Consider the counterclockwise sense as positive.The sum of the torques about the vertical axis through point O,acting on the plate due to forces F₁,F₂,and F₃,is closest to

A) 4.1 N • m
B) 5.4 N • m
C) -4.1 N • m
D) -5.4 N • m
E) zero