Ahelicopter flies 168 miles against the wind in 2 hours; with the wind, it can fly 252 miles in the same amount of time. find the speed of the helicopter in still air.

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

Answerapplying a direct current to a non magnetic material in order to create a electromagnetic field; plz check first good luck;