This Year, the IRS Audited Mr and Mr Simon's 2015

This year, the IRS audited Mr and Mr Simon's 2015 income tax return and determined that they underpaid their tax by $13,780. Which of the following statements is true?

A) If the revenue agent concludes that the Simons made a reasonable attempt to compute their tax, they will not pay anything as a result of the audit.
B) If the revenue agent concludes that the Simons made a reasonable attempt to compute their tax, they will pay a total of $13,780 as a result of the audit.
C) In addition to the $13,780 deficiency, the Simons must pay interest to the government regardless of the reason for the deficiency.
D) If the revenue agent concludes that the deficiency is attributable to the Simons' negligence in preparing their return, the agent may assess a $10,335 penalty.