The potential energy of the rotation of one ch3 group relative to its neighbouring ethane can be expressed as v(φ) = v0cos 3φ. show that for small displacements the motion of the group is quantized and calculate the energy of excitation from v= 0 to v= 1. what do you expect to happen to the energy levels and wavefunctions as the excitation increases to high quantum numbers?

Iwannasay c is the most accurate

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