A wire placed on the plane of this screen carries a current toward the top of the screen. The wire feels a magnetic force toward the right. The direction of the magnetic field causing this force is which of the following?

a. in the plane ofthe display and toward the left edge, b. in the plane ofthe display and toward the bottom edge, c. upward out of thedisplayd. downward into thedisplay.

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

The cell reaction uses external supplies of a full and an oxidant, which are consumed and needs to be provided continuously. the cell will continue to provide electrical energy so long as there is a supply of fuel and oxidant.  hope this ! (: