Correct Option
(c) On Earth, approximately 2.5% of the total water is freshwater. The vast majority of this freshwater, about 69%, is stored in ice caps and glaciers. Out of the remaining freshwater, the largest proportion, approximately 30%, exists as groundwater. This makes groundwater the second-largest reservoir of freshwater after ice and glaciers.
Incorrect Options
(a) Is found in atmosphere as moisture and clouds: Atmospheric moisture and clouds constitute a very small fraction, approximately 0.04%, of the total freshwater. This is significantly less than the proportion found as groundwater.
(b) Is found in freshwater lakes and rivers: Freshwater lakes and rivers collectively account for less than 0.3% of the total freshwater. This proportion is considerably smaller than that of groundwater.
(d) Exists as soil moisture: Soil moisture represents a relatively small amount of freshwater, significantly less than the volume stored as groundwater.