**Core Concept:** Lactose is a disaccharide sugar found in milk and other dairy products. When lactose is broken down or hydrolyzed, it can be converted into simpler monosaccharides, which are easily absorbed by the small intestine.

**Why the Correct Answer is Right:** When lactose is hydrolyzed, it is broken down into two monosaccharides: glucose and galactose. This process is carried out by the enzyme lactase, specifically lactase-phlorizin hydrolase, which is produced by the intestinal brush border cells. The resulting glucose and galactose can be easily absorbed by the enterocytes (intestinal cells) and transported to the bloodstream, providing energy for the body.

**Why Each Wrong Option is Incorrect:**

A. **Lactulose:** Lactulose is a disaccharide sugar that contains fructose instead of glucose. It is used as a medication to treat liver diseases, not as a result of lactose hydrolysis.

B. **Lactate:** Lactate is a carboxylic acid produced during anaerobic fermentation in the absence of oxygen. It is not a product of lactose hydrolysis.

C. **Maltose:** Maltose is a disaccharide sugar formed from the breakdown of starch (a polysaccharide) and is not a result of lactose hydrolysis.

D. **Lactase:** Lactase is an enzyme that catalyzes the hydrolysis of lactose into glucose and galactose, making it the correct answer and not a product of the reaction.

**Clinical Pearl:** A deficiency in lactase enzyme (lactase deficiency) can lead to lactose intolerance, causing abdominal pain, bloating, diarrhea, and other gastrointestinal symptoms when consuming lactose-rich foods. This is a common condition among lactose-intolerant individuals.