Uric acid crystal deposits under the skin in gout are known as:

Correct option is C

Tophi are the deposits of uric acid crystals that form under the skin in people with gout. These deposits are typically seen in chronic gout and can appear as lumps, usually around the joints.
Explanation of options: (a) ✘ Incorrect. Heberden’s nodes are bony growths at the distal joints seen in osteoarthritis, not gout. (b) ✘ Incorrect. Erythema nodosum is a skin condition characterized by red, tender lumps, often caused by infections or inflammatory conditions, but not related to uric acid crystals. (c) ✔ Correct. Tophi are the visible deposits of uric acid crystals in the skin, characteristic of long-term gout. (d) ✘ Incorrect. Erythema marginatum is a type of rash associated with rheumatic fever, not gout.