A very low friction merry-go-round (rotating platform) with a radius of 1.5 m and moment of inertia of 50 kgm2 is rotating at 10 rev/min. A child with a mass of 20 kg initially sits 1 m from the center, and then moves outward toward the edge of the platform. Which quantities are conserved in this scenario?

I. Angular Momentum

II. Rotational Kinetic Energy

III. Angular velocity

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