Which of the following induces increase in the length of grape stalks :

Options

A. Gibberllins
B. Cytokinin
C. IAA
D. Ethylene

Answer

To solve the question "Which of the following induces an increase in the length of grape stalks?", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Hormones**: First, we need to identify the hormones that are involved in plant growth and development. The options typically include gibberellins, cytokinins, auxins (like indole acetic acid), and ethylene.

2. **Understand the Function of Each Hormone**:
- **Gibberellins**: These are known to promote stem elongation and are crucial for the growth of grape stalks. They increase the length of stems and are particularly effective in enhancing the growth of fruits like grapes.
- **Cytokinins**: These hormones are primarily involved in promoting cell division and are not specifically known for increasing stem length.
- **Auxins (Indole Acetic Acid)**: Auxins are involved in various growth processes, including apical dominance and fruit development, but they do not primarily induce elongation of stems.
- **Ethylene**: This hormone is mainly associated with fruit ripening and does not play a significant role in stem elongation.

3. **Determine the Correct Answer**: Based on the functions of these hormones, we can conclude that gibberellins are the hormones responsible for inducing an increase in the length of grape stalks.

4. **Final Answer**: Therefore, the correct answer to the question is **gibberellins**.