detailed solution

Correct option is A

Energy  is defined as the ability to do work.

Power is defined as the rate at which energy is used or transmitted; it is equal to the amount of energy divided by the time it takes to use the energy. Its unit is the watt, which is one joule of energy used per second.

Power of electric bulb = 40W

                                        =0.04 kW

Time used, t = 5h

Energy = $\mathrm{Power} \times \mathrm{Time} \mathrm{taken}$

             $=0.04 kW \times 5 \mathrm{h}$

             $=0.2 kWh$

             $=0.2\left(units\right)$

The energy consumed by the tube light is 0.2 'units'.