If you ignore air resistance whow long will it take the container to fall 300m to the ground?

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

Idon't understand is there supposed to be a list or something if there is pm or add in under this message i will do my best to .

C. the electric current passes from the slip rings, through the brushes, and to the collection device.