A dolphin can typically hear sounds with frequencies up to 150,000 Hz. What is the velocity of sound in water if a wave with this frequency has a wavelength of 1.2 m?

A. to determine if humans can explore mars safely

This is kenetic energy.

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