Answer: c. used to record an adjustment to Bad Debt Expense for the year ending December 31, 2018
Step-by-step explanation:
Since the events occur after the balance sheet date, but before the balance sheet is issued, and gives more evidence about conditions that existed at the balance sheet date, then it should be used to record an adjustment to Bad Debt Expense for the year ending December 31, 2018
This is because an adjustment gives more information to the information already given in the balance sheet. Therefore, the correct option is C.