Synthetic plant hormone is

Options

A. IAA
B. 2, 4-D/NAA
C. GA
D. Zeatin.

Answer

**Step-by-Step Solution:**

1. **Understanding Plant Hormones**: Plant hormones, also known as phytohormones or plant growth regulators (PGRs), are substances that influence various physiological processes in plants, including growth, differentiation, senescence, and abscission.

2. **Identifying Types of Plant Hormones**: There are natural and synthetic plant hormones. Natural hormones include auxins, gibberellins, cytokinins, ethylene, and abscisic acid.

3. **Focusing on Auxins**: Among the plant hormones, auxins are a significant group. Indole Acetic Acid (IAA) is a well-known natural auxin.

4. **Recognizing Synthetic Auxins**: In addition to natural auxins, there are synthetic auxins. Two common synthetic auxins are 2,4-Dichlorophenoxyacetic acid (2,4-D) and Naphthalene Acetic Acid (NAA).

5. **Conclusion**: Since the question asks for a synthetic plant hormone, the correct answer is 2,4-D and NAA, which are both synthetic auxins.

**Final Answer**: The synthetic plant hormones are 2,4-D (2,4-Dichlorophenoxyacetic acid) and NAA (Naphthalene Acetic Acid).

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