When wheat and sugarcane leaves are fed with radioactive `.^(14)CO_(2)`. In which molecule would the radioactivity appear first in these plants?

Options

A. 3-Phosphoglycerate Oxalocacetate
B. 3-Phosphoglycerate 3-Phosphoglycerate
C. Oxalocaetate Oxaloacetate
D. Malate 3-Phosphoglycerate

Explanation

To determine in which molecule the radioactivity from radioactive \(^{14}CO_2\) would appear first in wheat and sugarcane leaves, we need to understand the differences between C3 and C4 plants and their respective pathways of photosynthesis.

### Step-by-Step Solution:

1. **Identify the Type of Plants**:
- Wheat is a C3 plant.
- Sugarcane is a C4 plant.

2. **Understand Photosynthesis Pathways**:
- C3 plants, like wheat, use the Calvin cycle during the dark reactions of photosynthesis. The first stable product formed in this pathway is **3-phosphoglycerate (3-PGA)**.
- C4 plants, like sugarcane, utilize the C4 pathway (or Hatch-Slack pathway). The first stable product formed in this pathway is **oxaloacetic acid (OAA)**.

3. **Radioactive Carbon Dioxide Feeding**:
- When both plants are fed with radioactive \(^{14}CO_2\), the incorporation of this carbon into organic molecules will follow the respective pathways of each plant.

4. **Determine the First Product of Radioactivity**:
- In wheat (C3 plant), the radioactivity will first appear in **3-phosphoglycerate (3-PGA)**.
- In sugarcane (C4 plant), the radioactivity will first appear in **oxaloacetic acid (OAA)**.

5. **Conclusion**:
- Therefore, the radioactivity will appear first in **3-phosphoglycerate for wheat** and **oxaloacetic acid for sugarcane**.

6. **Final Answer**:
- The correct option is **A: 3-phosphoglycerate (for wheat) and oxaloacetate (for sugarcane)**.