One end of a horizontal rope is attached to a prong of an electrically driven tuning fork that vibrates the rope transversely at 140 hz. the other end passes over a pulley and supports a 1.50 kg mass. the linear mass density of the rope is 0.0680 kg/m

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

'b ' is the correct conclusion.