10. What is the name of the structure shown with the number ''T' A. Anatomic apex B. Accessory canal Radioghraphic apex C. Cemento-dentinal junction D. Apical foramen

The correct answer is D. Apical foramen.<br /><br />The structure labeled with the letter "T" in the given diagram is the apical foramen. The apical foramen is the opening at the tip of the root of a tooth, allowing blood vessels and nerves to enter and exit the tooth. It is a crucial structure for the nourishment and sensory functions of the tooth.