Final answer:
The d)mandibular second premolar is the one that matches the description of having no transverse ridge, but a central fossa, 2 triangular fossae, and a lingual groove.
Step-by-step explanation:
The premolar that lacks a transverse ridge but has a central fossa, 2 triangular fossa, and a lingual groove is the mandibular second premolar (d). Premolars are one of the types of teeth situated on the sides of the jaws between the canine teeth and molars. They are used for crushing food, and their morphology can vary between the mandibular and maxillary arches as well as from the first to the second premolars.