Multiple choice botany energy flow in an ecosystem biogeochemical cycle nutrient cycles species, communities and ecosystems Source of maximum sulphur is/reservoir of sulphur is Ocean Lakes Land Rocks Reveal answer Fill a bubble to check yourself D Correct answer Explanation Source of maximum sulfur is/reservoir of sulfur is rocks. It is found in the form of iron pyrites, evaporite rocks in the form of anhydrite and baryte and calcium and magnesium carbonates.Thus, the correct answer is 'Rocks.'