To Determine Its Charge, an Oil Drop Is Suspended Motionless

Multiple Choice

To determine its charge, an oil drop is suspended motionless between two parallel plates that provide an electrostatic force acting on it. The following statement is true:

A) The oil drop has the same number of electrons as protons.
B) The oil drop is electrostatically neutral.
C) The weight of the drop is negligible.
D) The electrostatic force acting on the drop has the same magnitude as the weight of the drop, but points in the opposite direction.
E) None of the above is correct.