During drought, plants develop hormone

Options

A. Indole acetic acid
B. Naphthalene acetic acid
C. Indolebutyric acid
D. Abscisic acid.

Answer

### Step-by-Step Solution:

1. **Understanding the Context**: During drought conditions, plants experience water stress, which triggers physiological responses to conserve water.

2. **Identifying the Hormones**: The question asks which hormone is synthesized during drought conditions. The options provided include:
- Indole Acetic Acid (IAA)
- Naphthalene Acetic Acid (NAA)
- Indole Butyric Acid (IBA)
- Abscisic Acid (ABA)

3. **Recognizing the Correct Hormone**: Among the listed hormones, Abscisic Acid (ABA) is specifically known as the stress hormone. It is synthesized in response to water stress.

4. **Functions of Abscisic Acid**: ABA plays several crucial roles during drought:
- It promotes the closure of stomata, which reduces water loss through transpiration.
- It helps in water retention within the plant.
- It induces dormancy and inhibits seed germination, ensuring that the plant conserves resources during unfavorable conditions.

5. **Eliminating Incorrect Options**: The other hormones listed (IAA, NAA, IBA) are auxins, which are primarily involved in growth and development processes, not specifically in response to drought stress.

6. **Conclusion**: Therefore, the hormone that is developed and synthesized during drought conditions is Abscisic Acid (ABA).

### Final Answer:
The hormone synthesized during drought conditions is Abscisic Acid (ABA).

---