**Core Concept**
Gestational diabetes mellitus (GDM) is a type of diabetes that develops during pregnancy, typically in the second or third trimester. It is characterized by insulin resistance and impaired insulin secretion, leading to hyperglycemia. The pathophysiology of GDM involves the failure of pancreatic beta cells to produce sufficient insulin to meet the increased demand during pregnancy.

**Why the Correct Answer is Right**
The correct answer is related to the pathophysiological and clinical differences between gestational diabetes and other forms of diabetes. Gestational diabetes is distinct from type 1 diabetes, which is an autoimmune destruction of pancreatic beta cells, and type 2 diabetes, which is characterized by insulin resistance and impaired insulin secretion. Gestational diabetes also differs from pre-existing diabetes in terms of its onset and resolution post-pregnancy.

**Why Each Wrong Option is Incorrect**
**Option A:** Not applicable (we don't have the options A, B, C, D)

**Clinical Pearl / High-Yield Fact**
Gestational diabetes typically resolves post-pregnancy, but women with a history of GDM are at increased risk of developing type 2 diabetes later in life. Regular screening and monitoring are essential for these patients.

**Correct Answer:** Not available (since options were not provided)