Which enzyme deficiency is likely to cause a client discomfort after consuming milk?

The deficiency of lactase is specifically responsible for lactose intolerance, a condition that leads to discomfort after the consumption of milk and dairy products. Lactase is the enzyme required to break down lactose, the sugar found in milk. When a person has insufficient lactase, their body cannot adequately digest lactose, resulting in symptoms like bloating, gas, diarrhea, and abdominal pain after dairy consumption.

In contrast, the other enzymes listed serve different functions in carbohydrate digestion. Sucrase breaks down sucrose (table sugar), maltase is responsible for breaking down maltose (a sugar formed during the digestion of starch), and amylase begins the digestion of starches in the mouth and small intestine. Since they do not have a role in lactose digestion, deficiencies in these enzymes would not directly lead to discomfort from consuming milk, making lactase deficiency the clear and relevant answer.