Study of fresh water is called:

Correct option is A

Correct Answer: (a) Limnology
Explanation:
→ Limnology is the scientific study of inland waters — lakes, rivers, reservoirs, ponds — covering physical, chemical and biological aspects.
→ It includes ecosystem dynamics, productivity, and water quality.
Information Booster:
→ Oceanography studies marine environments; pedology is soil science; rheology studies flow behavior of materials.
Additional Information (Other Options):
(b) Oceanography: marine systems.
(c) Pedology: soils.
(d) Rheology: deformation and flow of matter.