If a machine has a mechanical advantage less than one which of the following must be true ?

a) the effort force is less then the resistance force

b) the effort distance is greater than the resistance distance

c) the effort distance is less then the resistance distance

d) the effort forces and resistance force are the same

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

Over 9