Take a bathroom scale into an elevator. Step on the scale.
What happens to the reading on the scale as the elevator begins to move upward? to move downward?

Ibelieve the answer is b

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

Ithink the answer would be a 

The correct answer is antinodes