Dover Company obtained a $50,000 line of credit from the bank on January 1, 2021. Dover agreed to accept a variable interest rate that was set at 1% above the bank's prime lending rate. The table below shows the amounts borrowed or repaid during the first three months of 2021 and the bank's prime rate of interest. Assume that Dover borrows or repays on the first day of each month. Month Prime Rate 7% January 2021 February 2021 Amount Borrowed (Repaid) $30,000 ($10,000) $15,000 7% March 2021 6% Rounded to the nearest dollar, the amount of interest expense Dover incurs in March 2021 is