If Earth's mass suddenly was cut in half, which of these would happen to your weight? A. It would decrease as the gravitational force increases.
B. It would increase as the gravitational force decreases.
C. It would decrease as the gravitational force decreases.
D. It would increase as the gravitational force increases.

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