Apex Corp. had accounts receivable of $197,000 (including $130,000 due in 1 month, $55,000 due in 3 months, and $12,000 past due) at the end of September. It estimated that uncollectible amounts are expected to be 2% of outstanding accounts receivable due in 1 month, 5% of those due in 3 months, and 25% of those past due. The allowance for doubtful accounts had a balance of of $5,500 (credit) at the beginning of September and $600 were written off during September. What is the amount of bad debt expense to be recorded at the end of September? a) $4,900 b) $2,250 c) $3,450 d) $2,850 e) $8,350