Indicate whether each of the following items is considered a primary authority or a secondary authority.
a. Private letter ruling from the IRS.
b. CCH Federal Tax Service.
c. BNA Tax Management Portfolios.
d. Treasury regulations.
e. IRS revenue procedure.
f. U.S. Tax Court memorandum decision.
g. U.S. Tax Court regular decision.
h. U.S. Supreme Court decision.
i. Internal Revenue Code section.
j. Article published in Journal of Corporate Taxation.