**Core Concept**
The transposition of teeth is a dental anomaly where two adjacent teeth in the dental arch switch positions, often resulting in malocclusion and aesthetic concerns. This condition can be classified as either true transposition or pseudotransposition, depending on the presence of a supernumerary tooth.

**Why the Correct Answer is Right**
The commonest teeth involved in true transposition are the maxillary canine and first premolar. This is due to the fact that the canine and first premolar often have similar eruption times, and their proximity to each other increases the likelihood of their transposition. The canine and first premolar are also often involved in other dental anomalies, such as supernumerary teeth and dens evaginatus, which can contribute to their transposition.

**Why Each Wrong Option is Incorrect**
**Option A:** The maxillary central incisor and lateral incisor are not commonly involved in transposition due to their relatively similar sizes and eruption times, which reduces the likelihood of their transposition.

**Option C:** The maxillary 1st premolar and 2nd premolar are less commonly involved in transposition compared to the canine and first premolar, as their eruption times and sizes are more distinct.

**Option D:** The maxillary canine and lateral incisor are not typically involved in transposition, as the canine and first premolar have a higher likelihood of being adjacent and switching positions.

**Clinical Pearl / High-Yield Fact**
When examining a patient with suspected dental anomalies, it is essential to evaluate the entire dental arch and consider the presence of supernumerary teeth, which can contribute to the transposition of adjacent teeth.

**✓ Correct Answer: B. Maxillary canine and first premolar**