Elements in groups 2 are all called alkaline earth metals. What is most similar about the alkaline earth metals

As newton's first law states a object in motion stays in motion

It equals just about 6,300 km per hour each day an week

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

45 is the correct answer