Which substance gets accumulated in abnormal amounts in Alkaptonuria: (A) Acetoacetate, (B) Oxalate, (C) Homogentisate, (D) Phenylacetic acid
Answer is C. Alkaptonuria:

Homogentisate oxidase deficiecy
Accumulation of Homogentisic acid.
Ochronosis: Deposition of alkaptone bodies in cartilages leading to pigmentation.