You are standing on the surface of a small spherical moon whose radius is 6.3 X 104 m and mass of 8 X 1018 kg. An astronaut throws a rock of mass 5 straight upward with a speed 20.0 m/s. (This Moon is too small to have an atmosphere.) What maximum height above the surface of the Moon will the rock reach

Ithink it’s cancer risk

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