**Core Concept**
Nutritional anemia, also known as iron-deficiency anemia, occurs due to inadequate dietary intake of essential nutrients, particularly iron. In pregnant women, increased iron demands during the second and third trimesters can lead to iron deficiency if dietary intake is insufficient.

**Why the Correct Answer is Right**
The most common oral change due to nutritional anemia is atrophic glossitis, characterized by smooth, red, and inflamed tongue surface. This is because iron is essential for maintaining healthy mucosal tissues, including the tongue. Iron deficiency impairs the production of keratin, leading to mucosal atrophy and inflammation.

**Why Each Wrong Option is Incorrect**
* **Option A:** While fatigue is a common symptom of anemia, it is not a specific oral change associated with nutritional anemia.
* **Option B:** Weight loss is a non-specific symptom of many conditions, including anemia, but is not a characteristic oral change.
* **Option C:** Bad breath (halitosis) can be associated with various oral conditions, but it is not the most common oral change due to nutritional anemia.

**Clinical Pearl / High-Yield Fact**
Atrophic glossitis is a classic sign of iron-deficiency anemia, and its presence should prompt investigation for iron deficiency, particularly in pregnant women.

**Correct Answer: C. Bad breath (halitosis) can be associated with various oral conditions, but it is not the most common oral change due to nutritional anemia.**