Pick up the incorrrect statement from the following.

Options

A. Glucose exists in two different crystalline forms , `alpha-`D-glucose and `beta-D`- glucose
B. Cyclic structure of `alpha-D-` glucose and `beta-`D-glucose is called pyranose structure.
C. `alpha-`D-glucose and `beta-`D-glucose are enantiomers.
D. Cellulose is a straight chain polysaccharide made up of only `beta`-glucose units.

Explanation

To solve the question "Pick up the incorrect statement from the following," we will analyze each statement regarding glucose and its forms.

### Step-by-Step Solution:

1. **Understanding Glucose Forms**:
- Glucose exists in two different crystalline forms: alpha-D-glucose and beta-D-glucose.
- These forms differ based on the position of the hydroxyl group (-OH) attached to the anomeric carbon (the first carbon in the cyclic structure).

2. **Identifying the Structures**:
- In alpha-D-glucose, the hydroxyl group on the anomeric carbon is on the right side when the molecule is drawn in the Haworth projection.
- In beta-D-glucose, the hydroxyl group on the anomeric carbon is on the left side.

3. **Analyzing the Statements**:
- **Statement A**: Glucose exists in two different crystalline forms (alpha-D-glucose and beta-D-glucose).
- This statement is **true**.
- **Statement B**: The crystalline structure of alpha-D-glucose and beta-D-glucose is called pyranose structure.
- This statement is **true** as both forms are cyclic and resemble a six-membered ring (pyranose).
- **Statement C**: Alpha-D-glucose and beta-D-glucose are enantiomers.
- This statement is **incorrect**. Alpha and beta forms are not enantiomers; they are anomers, which are a type of stereoisomer that differ at the anomeric carbon.
- **Statement D**: Cellulose is a polysaccharide made by beta-D-glucose.
- This statement is **true**. Cellulose is formed by the polymerization of beta-D-glucose units.

4. **Conclusion**:
- The incorrect statement is **Statement C**: "Alpha-D-glucose and beta-D-glucose are enantiomers."

### Final Answer:
The incorrect statement is **C**: "Alpha-D-glucose and beta-D-glucose are enantiomers."

---