I need help.

On September 1, Lewis Company had the following account balances: Accounts Receivable, $79,900; Allowance for Uncollectible Accounts, $3,480. On September 5, Lewis Company determines that the balance owed by their customer, Sanders Company, was uncollectible, and Sanders's account of $570 is written off. Required: (a) What is the net realizable value (NRV) of the accounts receivable on September 1? (b) What is the NRV on September 5? 1. Net realizable value on September 1 2. Net realizable value on September 5 $0