Consider the following statements in Citric Acid Cycle
1. The generation of ATP is done at two steps
2. NAD is reduced to NADH at two steps
3. FAD is reduced to `FADH_2`, at one step
Which of the statements given above is/are correct?

Options

A. 1 and 2 only
B. 3 only
C. 1 and 3 only
D. 1, 2 and 3

Answer

To solve the question regarding the statements about the Citric Acid Cycle, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1: The generation of ATP is done at two steps.**
- In the Citric Acid Cycle, ATP is generated primarily during one specific step: when succinyl CoA is converted to succinate. This process produces one molecule of ATP (or GTP, depending on the organism). Therefore, this statement is **incorrect**.

2. **Statement 2: NAD is reduced to NADH at two steps.**
- In the Citric Acid Cycle, NAD is reduced to NADH at three different steps:
- First, when isocitrate is converted to alpha-ketoglutarate.
- Second, when alpha-ketoglutarate is converted to succinyl CoA.
- Third, when malate is converted to oxaloacetate.
- Since NAD is reduced at three steps, this statement is also **incorrect**.

3. **Statement 3: FAD is reduced to FADH2 at one step.**
- In the Citric Acid Cycle, FAD is reduced to FADH2 during the conversion of succinate to fumarate. This is the only step where this reduction occurs. Therefore, this statement is **correct**.

### Conclusion:
Based on the analysis:
- Statement 1 is incorrect.
- Statement 2 is incorrect.
- Statement 3 is correct.

Thus, the only correct statement is **Statement 3**.

### Final Answer:
The correct answer is **3 only**.

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