2 Mobile phones use electromagnetic waves in a wavelength range that includes short-wave radio waves and microwaves.
a What would be the effect on mobile phone users if remote control
handsets operated in this range as well?

It is d, all the other ones say incorrect answer .

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