**Core Concept**
The question requires knowledge of carbohydrate digestion and the role of enzymes involved in this process. Carbohydrate digestion begins in the mouth and small intestine, where enzymes break down complex carbohydrates into simple sugars. One key enzyme responsible for this process is amylase.

**Why the Correct Answer is Right**
The correct answer is related to the deficiency of an enzyme that plays a crucial role in carbohydrate digestion. Specifically, this enzyme is a type of amylase that breaks down starches into simple sugars. The enzyme is produced in the pancreas and secreted into the small intestine, where it facilitates the digestion of carbohydrates. Without sufficient production or activity of this enzyme, carbohydrate digestion is impaired.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the enzyme associated with carbohydrate digestion is not lipase, which is involved in fat digestion.
* **Option B:** This option is incorrect because the enzyme associated with carbohydrate digestion is not lactase, which is involved in lactose digestion in the small intestine.
* **Option C:** This option is incorrect because the enzyme associated with carbohydrate digestion is not sucrase-isomaltase, which is involved in the breakdown of sucrose and other disaccharides in the small intestine.

**Clinical Pearl / High-Yield Fact**
A deficiency in the enzyme responsible for carbohydrate digestion can lead to malabsorption of carbohydrates, resulting in symptoms such as bloating, gas, and diarrhea.

**Correct Answer:** A. Amylase.