Glycogen occurs in

Options

A. Mitochondria
B. Kreb's cycle
C. Cytoplasm
D. None of these

Explanation

**Step-by-Step Solution:**

1. **Understanding Glycogen**: Glycogen is a polysaccharide that serves as a form of energy storage in animals. It is primarily made up of glucose units and is similar to starch, which is the storage form of carbohydrates in plants.

2. **Location of Glycogen**: Glycogen is predominantly found in the liver and muscle tissues of animals. It is stored in granules within the cytoplasm of cells, where it can be readily mobilized to meet energy needs.

3. **Analyzing the Options**: The question provides several options: mitochondria, Krebs cycle, cytoplasm, or none of these.
- **Mitochondria**: Known as the powerhouse of the cell, it is primarily involved in ATP production through cellular respiration but does not store glycogen.
- **Krebs Cycle**: This is a series of chemical reactions used by all aerobic organisms to generate energy. It occurs in the mitochondria but is not a storage site for glycogen.
- **Cytoplasm**: This is the fluid inside the cell where various organelles are suspended, and it is indeed where glycogen granules are stored.

4. **Conclusion**: Based on the analysis, glycogen occurs in the cytoplasm of cells, particularly in liver and muscle cells.

**Final Answer**: Glycogen occurs in the cytoplasm.

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