Choice "C" is correct. Following an audit, if agreement is reached with the taxpayer, the taxpayer signs Form 870 (Waiver of Restrictions on Assessment and Collection of Deficiency in Tax).Choice "a" is incorrect. Upon submission, all returns are checked for mathematical accuracy and to ensure that required items such as Social Security numbers and signatures are not missing. This check is made regardless of whether or not the return indicates a refund. Choice "b" is incorrect. Office audits are not normally performed at the national office of the IRS in Washington, DC. They are normally performed at local IRS offices. Choice "d" is incorrect. The Appeals Division, but not a revenue agent, can settle an unresolved tax issue based on the probability of winning the case in court.