Why Ohm's Law rearranged for current gives I = E / R. Here 240 volts divided by 24 ohms equals 10 amperes. Whenever you are given volts and ohms and asked for amps, divide the voltage by the resistance.
Watch out The 0.1 ampere choice comes from dividing the resistance by the voltage (24/240), which flips the formula upside down, and 5760 amperes is what you get by multiplying volts times ohms instead of dividing.
Amps = Volts over Ohms. 240/24 = 10. If your answer looks absurdly huge, you multiplied when you should have divided.