The PGR that could fit in both promotory and inhibitory groups but it is largely an inhibitor of growth activites is

Options

A. auxins
B. abscisic acid.
C. ethylene
D. either 1, 2 & 3.

Answer

To solve the question regarding the plant growth regulator (PGR) that fits into both promotory and inhibitory groups but is largely an inhibitor of growth activities, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Plant Growth Regulators (PGRs)**:
- PGRs are chemicals that regulate various aspects of plant growth and development. They can either promote or inhibit growth activities.

2. **Identifying the Options**:
- The options provided are:
1. Auxins
2. Abscisic Acid
3. Ethylene
4. Either 1, 2, or 3

3. **Analyzing Each Option**:
- **Auxins**: Primarily promote growth by stimulating cell elongation and are not known to be significant inhibitors.
- **Abscisic Acid**: Generally acts as an inhibitor, particularly in stress responses, but it does not fit into both categories prominently.
- **Ethylene**: This is a unique PGR that can promote growth (e.g., fruit ripening) and also inhibit growth activities (e.g., slowing down mitotic divisions, causing senescence).

4. **Determining the Correct Answer**:
- Since ethylene is known to promote certain growth processes while also inhibiting others, it fits the criteria of being both a promoter and an inhibitor. However, it is largely recognized for its inhibitory effects on growth activities, particularly in terms of slowing down growth and promoting leaf and flower abscission.

5. **Conclusion**:
- The PGR that fits the criteria of being both promotory and inhibitory but is largely an inhibitor of growth activities is **Option 3: Ethylene**.

### Final Answer:
**Option 3: Ethylene**