Which of the following is an example of ketohexose ?

Options

A. mannose
B. Galactose
C. maltose
D. fructose

Explanation

To determine which of the following is an example of a ketohexose, we need to analyze each option based on the definitions of hexose sugars and their functional groups.

### Step-by-Step Solution:

1. **Understanding Hexose Sugars**:
- Hexose sugars are monosaccharides that contain six carbon atoms. They can be classified into two categories based on their functional groups: aldoses (which contain an aldehyde group) and ketoses (which contain a ketone group).

2. **Identifying the Options**:
- The options given are:
1. Mannose
2. Galactose
3. Maltose
4. Fructose

3. **Analyzing Each Option**:
- **Option 1: Mannose**:
- Mannose is a hexose sugar and has an aldehyde group, making it an aldohexose. Therefore, it is not a ketohexose.

- **Option 2: Galactose**:
- Galactose is also a hexose sugar with an aldehyde group, which classifies it as an aldohexose. Hence, it is not a ketohexose.

- **Option 3: Maltose**:
- Maltose is a disaccharide formed from two glucose units. Since it is not a monosaccharide, it cannot be classified as either an aldohexose or a ketohexose.

- **Option 4: Fructose**:
- Fructose is a hexose sugar that contains a ketone group, making it a ketohexose. This is the correct option.

4. **Conclusion**:
- After analyzing all the options, we find that the only example of a ketohexose among the given choices is **Fructose** (Option 4).

### Final Answer:
**Option 4: Fructose** is an example of a ketohexose.