Adoption of Rule 15ba2-1, Related Form MSD, Rule 15ba2-2 and Temporary Rule 15ba2-3(T) Relating to the Registration Of Municipal Securities Dealers Under Section 15b(a) of the Securities Exchange Act of 1934; Adoption of Temporary Rule 15a-1 (T) Relating to the Registration Of Municipal Securities Brokers and Dealers Under Section 15 of the Act; and Delegation of Authority to the Staff of The Commission