A member wishes to provide nonattest services to Company O, an attest client. Which statement best describes a general requirement in the AICPA independence rules that the member must fulfill before performing the engagement?

a)The firm should have Company O's executives sign an indemnification agreement.

b) The firm should ensure that the attest and nonattest work will not be performed simultaneously.

c) The firm should agree to bill Company O for all nonattest services rendered.

d) The firm should reach an understanding with the attest client about the nonattest services engagement and document that understanding.