**Explanation:**

The correct answer is option D, Nutmeg.

**Desserts in Western Countries:**
In western countries, desserts play a significant role in their cuisine. These desserts are often sweet and indulgent, offering a delightful end to a meal. Various ingredients are used in the preparation of these desserts, but one spice that stands out is nutmeg.

**Nutmeg:**
Nutmeg is a spice that is derived from the seed of the nutmeg tree. It has a warm, aromatic flavor with a slightly sweet and nutty taste. Nutmeg is commonly used in both sweet and savory dishes, but it is particularly popular in desserts in western countries.

**Usage in Desserts:**
Nutmeg is used in a wide range of desserts due to its unique flavor profile. It adds depth and warmth to the dish, enhancing the overall taste. Some common desserts where nutmeg is used include:

1. **Pumpkin Pie:** Nutmeg is a key ingredient in pumpkin pie, a classic dessert in western countries. It complements the earthy flavor of pumpkin and enhances the overall taste of the pie.

2. **Apple Pie:** Nutmeg is often used along with cinnamon in apple pie recipes. It adds a warm and spicy note to the sweet and tart apples, creating a perfect balance of flavors.

3. **Rice Pudding:** Nutmeg is frequently sprinkled on top of creamy rice pudding. It adds a hint of warmth and elevates the flavor of the dessert.

4. **Bread Pudding:** Nutmeg is an essential ingredient in bread pudding recipes. It infuses the custard mixture with a rich and aromatic flavor that enhances the taste of the bread and other ingredients.

5. **Eggnog:** Nutmeg is a classic spice used in eggnog, a popular holiday drink in western countries. It adds a warm and festive touch to the creamy and spiced beverage.

**Conclusion:**
While there are various spices and flavors used in desserts in western countries, nutmeg stands out as a common and popular choice. Its warm and aromatic flavor adds depth and enhances the taste of a wide range of desserts. From pies to puddings, nutmeg plays a crucial role in creating delicious and indulgent sweet treats.