Which growth regulators is used to prepare weed-free lawns by the gardeners?

Options

A. Indole-S-acetic acid
B. Indole butyric acid
C. 2, 4-dichlorophenoxy acetic acid
D. Naphthalene acetic acid

Explanation

To answer the question about which growth regulator is used to prepare weed-free lawns by gardeners, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Types of Growth Regulators**:
- There are various plant growth regulators, including auxins, gibberellins, cytokinins, and others. In this context, we focus on auxins.

2. **Differentiate Between Natural and Synthetic Auxins**:
- Natural auxins include Indole Acetic Acid (IAA) and Indole Butyric Acid (IBA). These are involved in normal plant growth and development but are not used for weed control.

3. **Focus on Synthetic Auxins**:
- Synthetic auxins can be used as herbicides. One notable synthetic auxin is 2,4-Dichlorofenoxyacetic Acid (2,4-D).

4. **Understand the Function of 2,4-Dichlorofenoxyacetic Acid**:
- 2,4-D is specifically designed to target and kill weeds. It does this by causing uncontrolled growth in the weeds, leading to their demise while leaving the desired plants (like grass) unaffected.

5. **Conclusion**:
- Therefore, the growth regulator used by gardeners to prepare weed-free lawns is **2,4-Dichlorofenoxyacetic Acid**.

### Final Answer:
The growth regulator used to prepare weed-free lawns by gardeners is **2,4-Dichlorofenoxyacetic Acid**.

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