Lactase hydrolyzes lactose in milk Steps:

• Milk's primary sugar is lactose, a disaccharide.
• Lactase enzyme on jelly beads contacts the flowing milk.
• Lactase breaks lactose into glucose and galactose via hydrolysis.
• By point X, digestion completes, converting all lactose.

Why A is correct:

• Lactase catalyzes lactose + H₂O → glucose + galactose, leaving glucose (and galactose) without lactose.

Why the others are wrong:

• B: Complete digestion eliminates lactose, not leaving it only.
• C: Immobilized lactase stays on beads; milk retains product sugars.
• D: Lactose is a sugar, and it's fully digested anyway.

Final answer: A