Si se dispone de una balanza y de un dinamometro muy sensibles y que con aquella se mide la masa de un objeto de 25 kg en la tierra. Que señalarán la balanza y el dinamómetro si la medida se efectúa a 2000 m de altitud sobre la superficie de la tierra?

The answer is b hope this

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