Which cyst is known to form around the crown of an unerupted tooth?

The dentigerous cyst is specifically associated with the crowns of unerupted teeth, making it the correct choice. This type of cyst typically forms around the crown of an impacted tooth, most commonly the mandibular third molars or maxillary canines. It originates from the reduced enamel epithelium after the tooth's development and can be identified radiographically as a well-defined, unilocular radiolucency adjacent to the root of an unerupted tooth.

In contrast, other conditions listed, such as the nasopalatine duct cyst, globulomaxillary cyst, and fibrous dysplasia, do not fit this description. The nasopalatine duct cyst usually occurs in the midline of the anterior maxilla, while the globulomaxillary cyst is found between the roots of the maxillary lateral incisor and canine. Fibrous dysplasia is a bone disorder that can cause expansion but does not form in relation to any individual tooth's crown. Therefore, the uniqueness of the dentigerous cyst in relation to unerupted teeth clearly establishes it as the correct answer.