A magnetic flux density (B). 10T was obtained When a set of magnetic perpendically through a Cyclinderical surface of radus 500mm and leaght 300cm.
Calculate the magnitude of the flux if fallen on the
total surface of the cylindrical body​

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