In 2015, Sherri, a single taxpayer, had $3,600 in state tax withheld from her paycheck. She properly deducted that amount on her 2015 tax return as an itemized deduction that she qualified for, thus reducing her tax liability. After filing her 2015 tax return Sherri discovered that she had overpaid her state tax by $316. She received her refund in July 2016. What must Sherri do with the $316 refund? Explain your answer.