Indigo belongs to the class of

Options

A. Mordant dyes
B. Vat dye
C. Direct dye
D. Disperse dye

Explanation

**Step-by-Step Solution:**

1. **Identify Indigo**: Indigo is a natural dye that is commonly used for dyeing fabrics, particularly denim.

2. **Class of Indigo**: Indigo belongs to the class of "dyes." More specifically, it is categorized as a "vat dye." Vat dyes are insoluble in water and require a reduction process to become soluble for dyeing purposes.

3. **Properties of Indigo**: Indigo is insoluble in water in its original form. However, when it undergoes a reduction process, it becomes soluble. This reduction can be achieved through chemical reactions that convert indigo into a soluble form.

4. **Color of the Soluble Product**: After reduction, the soluble product can either be colorless or colored, depending on the conditions and the specific reactions that occur during the reduction process.

5. **Conclusion**: Therefore, indigo belongs to the class of vat dyes, which are used in various dyeing processes.

**Final Answer**: Indigo belongs to the class of vat dyes.

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