Letter of Consent; Cboe Rules 15.1 and 17.1 - Maintenance, Retention and Furnishing of Books, Records and Other Information, Cboe Rules 4.2 and 8.2 - Adherence to Law, and Cboe Rules 4.24 and 8.16 - Supervision; Section 17(a) of the Exchange Act and Rule 17a-3 - Records to Be Made by Certain Exchange Members, Brokers and Dealers, thereunder