My suggestion, Mr. Chair, would be to have all three. I think they would be available. If they can't attend, of course, that would be unfortunate, but let's have as many as possible.
I can't stress this enough: these are three different levels of disability. In a sense, they are three different groups. We often--and this comes from my disability background--regroup people with disabilities as though they're all the same. Well, there are fundamental differences between how a person in a wheelchair might evacuate an aircraft and how a person who is deaf or blind might do so.