Substrate for glycolysis is

Options

A. glucose
B. fructose
C. sucrose
D. all of these

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks for the substrate of glycolysis.

2. **Understand Glycolysis**: Glycolysis is a metabolic pathway that converts glucose into pyruvate, producing energy in the form of ATP in the process.

3. **Evaluate the Options**:
- **Option 1: Glucose**: This is the primary substrate for glycolysis. When glucose is broken down, it undergoes a series of enzymatic reactions to produce pyruvate, ATP, and other intermediates.
- **Option 2: Fructose**: While fructose can enter glycolysis, it is not the primary substrate; therefore, this option is incorrect.
- **Option 3: Sucrose**: Sucrose is a disaccharide that must be broken down into glucose and fructose before entering glycolysis, making this option incorrect as well.
- **Option 4: Other options**: Any other substrates listed are also incorrect as they do not serve as the primary substrate for glycolysis.

4. **Conclusion**: Based on the analysis, the correct answer is **Option 1: Glucose**, as it is the main substrate used in the glycolytic pathway.

---