Which of the following is not a disaccharide

Options

A. Lactose
B. Sucrose
C. Maltose
D. Starch.

Answer

To determine which of the following is not a disaccharide, we need to analyze each option provided:

1. **Lactose**:
- Lactose is composed of two monosaccharides: glucose and galactose.
- Therefore, lactose is a disaccharide.

2. **Sucrose**:
- Sucrose is made up of glucose and fructose, which are also two monosaccharides.
- Hence, sucrose is a disaccharide.

3. **Maltose**:
- Maltose consists of two glucose molecules linked together.
- Thus, maltose is a disaccharide.

4. **Starch**:
- Starch is a polysaccharide, which means it is made up of many glucose units linked together in long chains.
- Since starch is not made up of just two monosaccharides, it is not a disaccharide.

Based on the analysis, the correct answer is **starch**, as it is not a disaccharide but a polysaccharide.

### Summary of the Solution:
- Lactose, sucrose, and maltose are all disaccharides.
- Starch is a polysaccharide made of many glucose units.
- Therefore, the correct answer is **starch**.