20 22) Crystal Britt's credit card company charges an APR of 21 percent applied at a monthly periodic rate on the previous balance. Crystal's December statement showed: previous balance, $397.90, new purchases, $341.80, fees, $55, payments, $500, and purchase returns, 55699. What is her finance charge for December? A) $83.52 B) $6.96 $49.92 D) $4.16