What is the name of vitamin B₂? 

Riboflavin 

The correct answer is option 2. Riboflavin.

Here is an explanation of vitamin \(B_2\) and how it fits into the context of vitamins:

Riboflavin is the chemical name for vitamin \(B_2\). Vitamin \(B_2\) is crucial for several important biological functions: It is a key component of coenzymes, particularly flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which are involved in the electron transport chain and various metabolic processes.

Metabolism: It helps in the metabolism of carbohydrates, fats, and proteins.

Cell Function: Riboflavin is essential for maintaining healthy skin, eyes, and nerves.

Antioxidant: It also plays a role in protecting cells from oxidative damage.

The Role of Riboflavin in the Body:

Energy Production: Riboflavin is a part of the coenzymes FMN and FAD, which are critical in the oxidative reactions of the electron transport chain. This process is central to the production of ATP, the energy currency of the cell.

Metabolic Pathways: It supports the metabolism of macronutrients and is involved in the synthesis of various cofactors necessary for biochemical reactions.

Cellular Health: It contributes to the health of skin, eyes, and the nervous system by participating in various enzymatic reactions that support these tissues.

Other Vitamins for Comparison:

1. Biotin (Vitamin \(B_7\)): Supports metabolic processes, especially in the conversion of carbohydrates, fats, and proteins into energy. It is also important for healthy skin, hair, and nails.

2. Cyanocobalamin (Vitamin \(B_{12}\)): Essential for DNA synthesis, red blood cell formation, and neurological function. It is crucial for the maintenance of nerve cells and red blood cell production.

3. Ascorbic Acid (Vitamin C):

Acts as an antioxidant, aids in collagen synthesis, enhances iron absorption, and supports the immune system.

Summary:

Riboflavin (Vitamin \(B_2\)) is crucial for energy production and metabolism, as well as maintaining healthy skin, eyes, and nerves. Biotin is involved in nutrient metabolism and maintaining skin, hair, and nails. Cyanocobalamin is essential for blood formation and nerve health. Ascorbic Acid is known for its antioxidant properties and role in collagen synthesis and immune function. Thus, Riboflavin is the correct name for vitamin \(B_2\), distinguished by its vital roles in metabolic processes and cellular health.