Ahorizontal force fa of magnitude 20.0 n is applied to a 3.00 kg psychology book as the book slides a distance d = 0.500 m up a frictionless ramp at angle θ= 30.0°. (a) during the displacement, what is the net work done on the book by fa, the gravitational force on the book and the normal force on the book? (b) if the book has zero kinetic energy at the start of the displacement, what is its speed at the end of the displacement?

As newton's first law states a object in motion stays in motion

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