Correct Option: A

Lactose is a disaccharide sugar that is found most notably in milk and is formed from galactose and glucose. Lactose makes up around 2~8% of milk (by weight), although the amount varies among species and individuals. It is extracted from sweet or sour whey. The name comes from lac or lactis, the Latin word for milk, plus the -ose ending used to name sugars. It has a formula of C12H22O11. Food industry applications, both of pure lactose and lactosecontaining dairy by-products, have markedly increased since the 1960s. For example, its bland flavor has lent to its use as a carrier and stabiliser of aromas and pharmaceutical products. Lactose is not added directly to many foods, because it is not sweet and its solubility is less than other sugars commonly used in food. Infant formula is a notable exception where the addition of lactose is necessary to match the composition of human milk.