Two currents go into the page, and two are pointing out of the page. Point a is at the center of the square, and points b and c are in the middle of two of the sides. What is the direction of the magnetic field at point a? a. Down (to the bottom of the page).
b. Up (to the top of the page).
c. The magnetic field is zero at this point.
d. To the right.
e. To the left

Kiloleter, mega leterhope this !

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