**Core Concept**
The question is testing the knowledge of disulfiram-like reaction, a phenomenon that occurs when a particular medication interacts with alcohol, leading to an unpleasant reaction. This reaction is characterized by symptoms such as flushing, nausea, vomiting, and headache.

**Why the Correct Answer is Right**
The disulfiram-like reaction is caused by the inhibition of aldehyde dehydrogenase, an enzyme involved in the metabolism of alcohol. The oral hypoglycemic drug that causes this effect is chlorpropamide. Chlorpropamide inhibits aldehyde dehydrogenase, leading to the accumulation of acetaldehyde, a toxic metabolite of alcohol. This accumulation causes the disulfiram-like reaction.

**Why Each Wrong Option is Incorrect**
**Option A:** Metformin does not cause a disulfiram-like reaction. It works by decreasing glucose production in the liver and increasing insulin sensitivity.
**Option B:** Glipizide is a sulfonylurea that stimulates insulin release from the pancreas. It does not cause a disulfiram-like reaction.
**Option C:** Pioglitazone is a thiazolidinedione that improves insulin sensitivity. It does not cause a disulfiram-like reaction.

**Clinical Pearl / High-Yield Fact**
It is essential to advise patients taking chlorpropamide or other medications that cause a disulfiram-like reaction to avoid consuming alcohol, as it can lead to a severe reaction.

**Correct Answer:** D. Chlorpropamide