Which amount of power is the smallest

I think this question is intended to compare units of power and choose the smallest one.

Since no choices are given, I will just tell you what each prefix equals and you can compare that to your choices:

gigawatt = 10^9 watt

megawatt = 10^6 watt

kilowatt = 10^3 watt

watt = 1 watt

So, if you have these units in your choices, the smallest amount of power will be the one having "watt" as a unit.