**Core Concept**
The maxillary teeth have single antagonists, which are the opposing teeth in the mandible that occlude with them during mastication. The maxillary and mandibular teeth have a specific arrangement to ensure proper occlusion and tooth function.

**Why the Correct Answer is Right**
Third molars, also known as wisdom teeth, have a unique relationship with their antagonists. In the maxillary arch, the third molar has a single antagonist, which is the second molar in the mandibular arch. This is because the third molar is often located in a more posterior position, allowing it to have a single opposing tooth in the mandible. The maxillary third molar's single antagonist is in contrast to other maxillary teeth, which often have multiple antagonists.

**Why Each Wrong Option is Incorrect**
**Option A:** The lateral incisors have multiple antagonists, including the central incisors and canines in the mandibular arch. This is because the lateral incisors are positioned more anteriorly, allowing them to occlude with multiple teeth in the mandible.

**Option B:** The permanent canines have multiple antagonists, including the central incisors and lateral incisors in the mandibular arch. This is because the canines are positioned more posteriorly in the maxillary arch, allowing them to occlude with multiple teeth in the mandible.

**Option C:** The permanent central incisors have multiple antagonists, including the lateral incisors and canines in the mandibular arch. This is because the central incisors are positioned more anteriorly, allowing them to occlude with multiple teeth in the mandible.

**Clinical Pearl / High-Yield Fact**
The single antagonist relationship of the third molar is a key concept in dental occlusion. Understanding this relationship is crucial for proper diagnosis and treatment of dental malocclusions and orthodontic issues.

**✓ Correct Answer: D. Third molars**