Step 1: Define invert sugar.
Invert sugar is a mixture of glucose and fructose, which is formed by the hydrolysis of sucrose. The hydrolysis reaction breaks the glycosidic bond between glucose and fructose molecules in sucrose.
Step 2: Analyze the options.
- Sucrose: Hydrolysis of sucrose results in the formation of invert sugar, consisting of glucose and fructose.
- Maltose: Maltose is a disaccharide composed of two glucose molecules and does not form invert sugar.
- Starch: Starch is a polysaccharide and its hydrolysis forms glucose, but not invert sugar.
- Lactose: Lactose is a disaccharide composed of glucose and galactose, and its hydrolysis does not form invert sugar.
Step 3: Final Answer.
Thus, the correct answer is option \((1)\) Sucrose.