How to answer investment application question

[Basically]

Client is completing an application to invest in a new asset. He is a single person plan investing in a limited partnership. One of the questions is below. How would he answer the question without being too vague (i.e. investor is a qualified retirement plan)

"If the investor is exempt from US Federal Income Tax, please indicate the basis for the exemption:"

Thanks!

[four01kman]

Internal Revenue Code Section 501(a)