With regard to Private Letter Rulings, taxpayer may a. cite them in a defense against adjustments in the Tax Court under Federal Rules of Evidence sec. 2099. b. cite them to avoid the substantial understatement penalty under code sec. 6662(d)(2)(B)(1). c. cite them in defense against a Jeopardy Assessment under code sec. 6861. d. cite them in defense against a jeopardy levy under code sec. 6331(a). e. none of the above.