The compounds A,B and C in the following reaction sequence are -

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The reaction sequence involves hydrolysis of carbohydrates. Starch is a polysaccharide that hydrolyzes to maltose (a disaccharide) upon treatment with dilute acid. Maltose further hydrolyzes to glucose (a monosaccharide). Thus, A is starch, B is maltose, and C is glucose.
Final Answer: starch, maltose, glucose