Final answer:
The molars are the permanent teeth most frequently ankylosed, often due to issues such as impaction, especially when it comes to wisdom teeth. Therefore, the correct option is C.
Step-by-step explanation:
The permanent teeth most frequently ankylosed are the molars. Ankylosis is a condition where the tooth becomes fused to the jaw bone, preventing it from erupting or moving normally. The molars, particularly the wisdom teeth, are more prone to becoming ankylosed due to their position in the back of the mouth and the common issues with impaction and failure to erupt properly. There are 12 molars in the permanent dentition, which includes the wisdom teeth, and these teeth play an essential role in crushing and grinding different kinds of foods.