Which one of the following plants has ovary superior, monocarpellary and unilocular with several ovules on marginal placenta ?

Options

A. Triticum
B. Helianthus annus
C. Pisum sativum
D. Allium cepa

Answer

To solve the question, we need to identify the characteristics of the plants listed in the options and determine which one has the following features:

1. **Ovary superior**: This means that the ovary is positioned above the point of attachment of other floral parts.
2. **Monocarpellary**: This indicates that the flower has only one carpel (the female reproductive structure).
3. **Unilocular**: This means that the ovary has only one chamber.
4. **Several ovules on marginal placenta**: This refers to the arrangement of ovules along the inner edge of the ovary.

Now, let's analyze the options provided:

1. **Trictylchum**: This plant does not typically have the specified characteristics.
2. **Helianthus annuus (Sunflower)**: This plant has a different ovary structure and is not monocarpellary.
3. **Pisum sativum (Pea)**: This plant is known to have a superior ovary, is monocarpellary, unilocular, and has several ovules arranged on the marginal placenta.
4. **Allium cepa (Onion)**: This plant does not fit the criteria as it has a different ovary structure.

Based on this analysis, the correct answer is **Pisum sativum**.

### Step-by-Step Solution:
1. **Identify the characteristics needed**: Superior ovary, monocarpellary, unilocular, and marginal placentation.
2. **Examine each option**: Check if they meet the criteria.
3. **Determine the correct plant**: Identify which plant fits all the characteristics.
4. **Conclude with the answer**: The correct answer is **Pisum sativum**.