The right answer is b. Glucose + fructose -> sucrose
Sucrose is a carbohydrate composed of a molecule of glucose associated with a molecule of fructose by a glycosidic bond. It is therefore a diholoside (or disaccharide in the old nomenclature). They also called α-D-glucopyranosyl- (1↔2) -β-D-fructofuranoside and its formula is C12H22O11.