Nic has a revolving dept store credit card account with rate 15%annually. Lastmonth balance on the account was $423.78. During the current month, he made purchases totalling $123.42 and made a payment of $100.00. The store uses the unpaid balance method. What must be the amt of balance charge, rounded to nearest cent. a. $5.30 b. $4.59 c. $6.36 d. $6.71