Answer:
$0
Explanation:
Since Tom and Betsy didn't itemize their deductions in 2018 (they chose the standard deduction), they didn't include the state taxes in their tax filing. Since the state taxes were not used by Tom and Betsy to reduce their federal income taxes, then any refund will not be included in their current income. Only if state taxes are used to lower federal taxes, do taxpayers need to include any refund.