The IRS revenue agent who audited Mr. and Mrs. Marlow's 2015 Form 1040 assessed a $49,200 tax deficiency. The Marlow's strongly disagree with the result of the audit. What is their first step in contesting the result? They may request that a different revenue agent conduct a second audit.

They must file a petition with the U.S. Tax Court.

They must appeal the result of the audit to the regional Appeals Office of the IRS.

They must pay the deficiency and sue the federal government for a refund.