Cracking the SAT Physics Subject Test

Which one of the following arrows best illustrates the total
electrostatic force on the charge in the lower right-hand corner of
the square?

(A)

(B)

(C)

(D)

(E) The electric force on this charge is 0.

61. One end of a rigid, massless rod of length 50 cm is attached to
    the edge of the table at point O; at the other end of the rod is a ball
    of clay of mass m = 0.2 kg. The rod extends horizontally from the
    end of the table. What is the torque of the gravitational force on the
    clay ball relative to point O?

(A) 0.01 N·m

(B) 0.1 N·m

(C) 1 N·m

(D) 10 N·m