At some point in a wire, you observe 4 × 10^18 electrons pass by in 0.5 s. What is the current flowing?

Gravity bc it’s gravity

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

Ibelieve the answer is b

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