The correct option is
A Partial hydrolysis of starch
Dextrin is a type of carbohydrate, having the same general formula as starch but a smaller and less complex molecule. They are polysaccharides and are produced as intermediate products in the hydrolysis of starch by heat, by acids, and by enzymes. Their nature and their chemical behaviour depend to a great extent on the kind of starch from which they are derived.
So, the correct answer is option B.