Which three characteristics make iron a good blackbody radiator? A. It emits several different wavelengths of EMR.
B. It does not emit EMR when hot.
C. It absorbs much of the EMR it receives.
D. It changes color when exposed to EMR that heats it.

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

What are you asking