The hypothetical citation Rev. Rul. 2013-20, 2013-12 I.R.B. 218 refers to which of the following?

a. A Revenue Ruling that can be found on page 218 of the 2013-12 volume of the Internal Revenue Bulletin

b. A Revenue Ruling that can be found on page 20 of the 2013-12 volume of the Internal Revenue Bulletin

c. A Revenue Ruling that can be found on page 12 of the 2013-20 volume of the Internal Revenue Booklet

d. A Revenue Ruling that can be found on page 218 of the 2013-12 volume of the Internal Revenue Booklet