In `C_(4)` plants , the first product is
(a) 3-PGA
(b) OAA
(c) Malic acid
(d) Glutamic acid

Options

A. 3-PGA
B. OAA
C. Malic acid
D. Glutamic acid

Answer

To solve the question regarding the first product formed in C4 plants, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding C4 Photosynthesis**:
- C4 plants utilize a unique pathway for photosynthesis that involves the fixation of carbon dioxide into a four-carbon compound.

2. **Identifying the Initial Reaction**:
- In C4 photosynthesis, carbon dioxide (CO2) is initially fixed by a three-carbon compound called phosphoenolpyruvate (PEP).

3. **Role of Enzyme**:
- The enzyme PEP carboxylase catalyzes the reaction between CO2 and PEP, leading to the formation of a four-carbon compound.

4. **Formation of the First Product**:
- The first product formed in this reaction is oxaloacetate (OAA), which is a four-carbon compound.

5. **Further Conversion**:
- Oxaloacetate can then be converted into other compounds, such as malate, but the question specifically asks for the first product formed.

6. **Conclusion**:
- Therefore, the correct answer to the question is (b) OAA (oxaloacetic acid).

### Final Answer:
(b) OAA

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