Consider the following statement.
D-glucose, D-galactose and D-fructose are all.
1. Isomers
2. Epimers
3. Aldohexoses
4.Monosaccharides .

Options

A. 1 and 4
B. 2 and 4
C. 1,2and 4
D. 1,2 and 4

Answer

To analyze the statement regarding D-glucose, D-galactose, and D-fructose, we need to evaluate each of the options provided:

1. **Isomers**: Isomers are compounds that have the same molecular formula but different structural formulas. D-glucose, D-galactose, and D-fructose all have the molecular formula C6H12O6, but they differ in structure. Therefore, they can be considered isomers. This option is correct.

2. **Epimers**: Epimers are a specific type of isomer that differ in configuration at only one specific carbon atom. D-glucose and D-galactose are epimers because they differ at the C-4 carbon. However, D-fructose is not an epimer of either D-glucose or D-galactose. Therefore, this option is incorrect.

3. **Aldohexoses**: Aldohexoses are six-carbon sugars that contain an aldehyde group. D-glucose and D-galactose are both aldohexoses, while D-fructose is a ketohexose (it contains a ketone group). Therefore, this option is incorrect.

4. **Monosaccharides**: Monosaccharides are the simplest form of carbohydrates and cannot be hydrolyzed into simpler sugars. D-glucose, D-galactose, and D-fructose are all monosaccharides. Therefore, this option is correct.

Based on the analysis:

- **Correct Options**: 1 (Isomers) and 4 (Monosaccharides)
- **Incorrect Options**: 2 (Epimers) and 3 (Aldohexoses)

### Final Answer:
D-glucose, D-galactose, and D-fructose are all isomers and monosaccharides.