Diane accidentally omitted from her 2012 tax return $ 40,000 of the gross receipts that she collected as the owner of a restaurant. Her 2012 return indicated collective gross receipts of $ 25,000. The IRS no longer can pursue Diane with the threat of collection of the related tax, interest, and penalties, as of April 15, ___
a. 2014
b. 2017
c. 2019
d. 2020
e. There is no expiration date for the statute of limitations in this context.