Which of the Following Statements Is True of Retention Pins

Multiple Choice

Which of the following statements is true of retention pins?

A) In general, three pins are inserted to replace each missing cusp.
B) The retention pin has deep threads that grip the dentin when screwed into tooth structure.
C) Pins are always 0.023 mm in diameter and extend 2 mm into tooth structure.
D) Pins are placed into the root canal of the tooth.