Which of the Following Is (Are)true About Topical Anesthetics

Multiple Choice

Which of the following is (are) true about topical anesthetics?

A) Topical anesthetics are most effective when placed on dry tissue for 1 to 2 minutes.
B) When applied properly,topical anesthetics can penetrate 2 mm into the tissue.
C) Topical anesthetics have very limited effect on keratinized tissue,such as the palate.
D) All of the above are true.
E) Both A and C are true.