The hormone that promotes female flowers in cucumbers is:

Options

A. Auxins
B. Gibberellins
C. Cytokinins
D. Ethephon

Answer

To solve the question regarding which hormone promotes female flowers in cucumbers, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the hormone that specifically promotes female flowers in cucumbers.

2. **Identify the Options**: The options provided are:
- A. Auxins
- B. Gibralins
- C. Cytokinins
- D. Ethyphon

3. **Research Each Option**:
- **Auxins**: These are plant hormones that primarily promote cell elongation and are involved in various growth processes, but they do not specifically promote female flowers in cucumbers.
- **Gibralins**: These hormones are known for promoting stem elongation and seed germination, but they do not have a direct role in promoting female flowers.
- **Cytokinins**: These hormones promote cell division and have various roles in plant growth, but they do not specifically promote female flowers in cucumbers.
- **Ethyphon**: This is an ethylene-releasing compound that promotes the development of female flowers in cucumbers and other cucurbits.

4. **Select the Correct Answer**: Based on the research, Ethyphon (option D) is the hormone that promotes female flowers in cucumbers.

5. **Conclusion**: Therefore, the correct answer to the question is **D. Ethyphon**.