Answer:
(a) It can be replenished as it is used.
Step-by-step explanation:
A resource is "renewable" if using it does not diminish the supply. Solar power and wind power are supplied by the Sun. The use of solar power and/or wind power does not change the capacity of the sun to provide that power.
A renewable resource is one that can be replenished as it is used.
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Additional comment
For all resources, there is a finite supply available on Earth. The sun supplies about 1 kW per square meter. Using some of that for human purposes changes the amount or form available for other purposes—photosynthesis, weather, ocean currents, reflection back to space, and so on. Within the time scale of human existence, the supply is essentially non-diminishing. With large-scale use, planet-wide effects can be expected.