**Core Concept**
Allergic rhinitis is an inflammatory condition of the nasal mucosa triggered by allergens, leading to the release of various chemical mediators. These mediators play a crucial role in the development of symptoms such as sneezing, nasal congestion, and rhinorrhea.

**Why the Correct Answer is Right**
The early mediators of allergic rhinitis include histamine, leukotrienes, and bradykinin. Histamine is released from mast cells and causes vasodilation, increased vascular permeability, and smooth muscle contraction. Leukotrienes, produced by the action of 5-lipoxygenase on arachidonic acid, also contribute to inflammation and mucus production. Bradykinin, a peptide formed by the action of kallikrein on kininogen, causes vasodilation and increased vascular permeability.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify any particular mediator of allergic rhinitis.
**Option B:** This option is incorrect because it is a late mediator of allergic rhinitis, which is involved in the sustained inflammatory response.
**Option C:** This option is incorrect because it is a mediator of inflammation, but not a primary mediator of allergic rhinitis.

**Clinical Pearl / High-Yield Fact**
The use of antihistamines and mast cell stabilizers can provide relief from symptoms of allergic rhinitis by blocking the action of histamine and reducing mast cell degranulation.

**Correct Answer: D. Histamine, leukotrienes, and bradykinin.**