Don't feel the need to send descriptions for every position within the company
There is a very good chance that this question will be asked toward the end of the interview when you have a good idea of what the interviewer is qualified for. Sending them relevant job descriptions based on his or her experience level will provide the greatest benefit.
Your response to providing job descriptions should be framed like this:
Absolutely. I'll have my assistant email you a couple job descriptions later this afternoon. I already have a few in mind that would be really good for someone with your background.
It is important to remember that the job descriptions do not have to be specifically from your company. They can also be from companies that are in the same line of work as yours. It does not even matter if the jobs you send are currently open. They should just be used as a future reference.