please help with the journal entry for a, b, and c

Prepare one journal entry summarizing the recognition of uncollectble accounts expense for the entire year under each of the following independent assumptions: a. Uncollectible accounts expense is estimated at an amount equal to 2.5 percent of netcredit sales. b. Uncollectible accounts expense is recognized by adjusting the balance in the Allowance for Doubtful Accounts to the amount indicated in the year-end aging schedule. The balance in the allowance account at the beginning of the current year was a $25,000 credit. (Consider the effect of the write-offs during the year on the balance in the Allowance for Doubtful Accounts.) c. The company uses the direct write-off method of accounting for uncollectible accounts