A patient with isolated congenital lactase deficiency ingests a meal containing lactose, maltose, and sucrose. Which set of monosaccharides will be absorbed in greatest proportion from this meal compared to a person with normal lactase activity?

• A. Markedly increased fructose absorption only, because absence of lactase upregulates sucrase activity and thereby disproportionately increases fructose production and uptake, a compensatory mechanism not supported by brush-border enzyme regulation.
• B. Complete absence of glucose absorption because all intestinal glucose transporters are downregulated in lactase deficiency, a claim inconsistent with transporter specificity and independent regulation of different sugar pathways.
• C. A proportionally greater plasma galactose concentration because bacterial fermentation in the colon converts lactose into galactose that is then absorbed directly into the portal circulation at higher rates than enterocyte absorption, a mechanism that misrepresents colonic fermentation products and absorption routes.
• D. Glucose and fructose levels similar, but reduced galactose absorption leading to relatively lower galactose in the bloodstream compared with a person who has normal lactase activity.

Answer: (D)