**Core Concept**
Second-generation antihistamines are a class of medications used to treat allergic reactions, including allergic rhinitis. They work by selectively inhibiting the histamine H1 receptor, thereby reducing symptoms such as itching, sneezing, and runny nose. These medications are preferred over first-generation antihistamines due to their lower sedative effects.

**Why the Correct Answer is Right**
Second-generation antihistamines, such as loratadine, cetirizine, and fexofenadine, are effective in treating allergic rhinitis due to their high affinity for the histamine H1 receptor and low affinity for the brain's histamine receptors, which are responsible for sedation. This selective action allows patients to experience relief from allergic symptoms without significant drowsiness. The mechanism of action involves competitive inhibition of histamine at the H1 receptor, which is a key step in the allergic response.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not a second-generation antihistamine used in allergic rhinitis.
**Option B:** This option is incorrect because it is not a correct example of a second-generation antihistamine used in allergic rhinitis.
**Option C:** This option is incorrect because it is not a second-generation antihistamine used in allergic rhinitis.

**Clinical Pearl / High-Yield Fact**
When choosing an antihistamine for allergic rhinitis, it's essential to select a second-generation medication to minimize sedation and ensure effective symptom relief. Additionally, these medications can be used in patients with cardiovascular disease, as they do not significantly affect heart rate or blood pressure.

**Correct Answer: D.**