Mr and Mrs Clyde Were Married for 21 Years Before

Mr and Mrs Clyde were married for 21 years before Mrs Clyde divorced her husband in 2017. This year, the IRS determined that the Clydes underpaid their 2016 tax by $19,650. In which case would Mrs Clyde be relieved of liability for the underpayment under the innocent spouse rule? 

A) Mrs Clyde did not read through the Form 1040 before she signed it.
B) Mrs Clyde remarried this year and is now Mrs Novak.
C) Mr. Clyde was the sole income earner during the entire marriage.
D) None of the above.