The correct answer is option 2: Casein, Lactose.

Casein is a protein that is present in milk. It makes up about 80% of the total protein content in milk. Lactose, on the other hand, is a sugar that is also found in milk. It is a disaccharide composed of glucose and galactose molecules.

Option 1, Casein and Sucrose, is incorrect because sucrose is not naturally present in milk.

Option 3, Ferritin and Maltose, is incorrect because ferritin is not a protein found in milk, and maltose is also not naturally present in milk.

Option 4, Albumin and Glucose, is incorrect because albumin is not a protein that is primarily found in milk, and glucose is a monosaccharide, not a sugar typically found in milk.

Therefore, the correct protein-sugar pair present in milk is Casein and Lactose.