The branch of mechanics dealing with the mathematical methods of describing motion is calle

This branch of mechanics is called kinematics. A way to remember this is to remember that energy in motion is called kinetic energy. So, kinematics deals with describing motion. 

The answer is c 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