The electric field near the surface of earth points downward and has a magnitude of 170 n/c. (a) compare the upward electric force on an electron with the downward gravitational force. (upward force / downward force) the gravitational force is is much larger. the electric force is is much larger. d both forces are equal. (b) what magnitude charge should be placed on a penny of mass 2 9 so that the electric force balances the weight of the penny near earth's surface?

Ohm's law tells you that i = v/r where v is equivalent voltage and r is equivalent resistance of the circuit
since all circuits have the same voltage, your question is really asking which circuit has the lowest total resistance, since the lower the resistance, the higher the current
circuit a has a resistance of 5 ohms; circuit c is in series so has a resistance of 10 ohms; circuit b is in parallel and therefore has a resistance of 2.5 ohms (review your notes on adding resistances in parallel and series); therefore b has the highest current