Reasonable methods for consumers to opt out include ______
a) Designating a check-off box in a prominent position on the opt-out form
b) Including a reply form and a self-addressed envelope together with the opt-out notice
c) Providing an electronic means to opt out, such as a form that can be electronically mailed or processed at a Web site, if the consumer agrees to the electronic delivery of information
d) all of the above