Reducing power `NADH + H^(+)` is produced during conversion step of glycolysis.

Options

A. 3-phosphoglyceric acid to 2-phosphoglycerate
B. Glyceraldehyde-3-phosphate to 1,3-bisphosphoglyceric acid
C. 2-phosphoglycerate to phosphoenol pyruvate
D. Phosphoenol pyruvate to pyruvic acid

Answer

To solve the question regarding the production of reducing power `NADH + H^(+)` during glycolysis, we will analyze each option provided in the question step by step.

### Step-by-Step Solution:

1. **Understanding Glycolysis**: Glycolysis is the metabolic pathway that converts glucose into pyruvate, releasing energy in the form of ATP and NADH. It consists of two phases: the preparatory phase and the payoff phase.

2. **Identifying the Phases**:
- **Preparatory Phase**: This phase consumes energy (ATP) and does not produce NADH.
- **Payoff Phase**: This phase produces energy in the form of ATP and NADH.

3. **Analyzing Each Option**:
- **Option A**: 3-phosphoglyceric acid to 2-phosphoglycerate
- This reaction involves an isomerization and does not produce NADH. Thus, this option is incorrect.

- **Option B**: Glyceraldehyde 3-phosphate to 1,3-bisphosphoglyceric acid
- This reaction occurs in the payoff phase and is where NADH is produced. Therefore, this option is correct.

- **Option C**: 2-phosphoglycerate to phosphoenolpyruvate
- This reaction involves the release of water but does not produce NADH. Thus, this option is incorrect.

- **Option D**: Phosphoenolpyruvate to pyruvic acid
- This reaction produces ATP but does not produce NADH. Therefore, this option is also incorrect.

4. **Conclusion**: Based on the analysis, the correct option that indicates the production of reducing power `NADH + H^(+)` during glycolysis is **Option B**: Glyceraldehyde 3-phosphate to 1,3-bisphosphoglyceric acid.

### Final Answer:
**The correct option is B: Glyceraldehyde 3-phosphate to 1,3-bisphosphoglyceric acid.**