Generally, a practitioner may not charge a contingent fee for services rendered in connection with any matter before the Internal Revenue Service. However, there are circumstances where a contingent fee is allowed. Which of the following statements is correct? Question 2Select one: a. A practitioner may not charge a contingent fee for services rendered in connection with the IRS' examination of, or challenge to an original tax return b. A practitioner may charge a contingent fee for services rendered in connection with an amended return or claim for refund or credit where the amended return or claim for refund or credit was filed within 120 days of the taxpayer receiving a written notice of the examination of, or a written challenge to the original tax return c. A practitioner must charge a contingent fee for services rendered in connection with any judicial proceeding arising under the Internal Revenue Code d. All of the above are correct statements regarding contingent fees