Among the options provided, which acid is classified as a vitamin?

1. Aspartic and 2. Ascorbic acid
3. Adipic acid 4. Saccharic acid

Hint: Vitamin C

Ascorbic acid is the chemical name of vitamin C. 
While others are not vitamins
 aspartic acid is an amino acid.          
Adipic acid is a dicarboxylic acid having 6 carbon chain.
Saccharic acid is a dicarboxylic acid obtained by oxidation of glucose using HNO3.