Which one of the following is a vitamin ?

Folic acid is a water-soluble B-vitamin, specifically known as Vitamin B9 [1]. It is essential for human health, particularly in preventing neural tube defects like spina bifida during pregnancy [1]. While folate occurs naturally in foods like dark green leafy vegetables and citrus fruits, folic acid is the synthetic form used in supplements and fortified foods [2]. In contrast, the other options are not vitamins: Citric acid is an organic acid found in citrus fruits like lemons and oranges [c1]; Glutamic acid is an amino acid that acts as a neurotransmitter; and Linoleic acid is an essential omega-6 fatty acid. Folic acid is regularly removed from the body through urine, necessitating consistent dietary intake or supplementation to maintain adequate levels for cellular function and metabolic health [2].

Sources

1. [1] https://medlineplus.gov/ency/article/002408.htm
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 2: Acids, Bases and Salts > Table 2.3 Some naturally occurring acids > p. 28