Debits increase receivables in the sales ledger control account Steps:

• Identify the sales ledger control account as summarizing total customer balances (debtors/receivables).
• Note debit entries increase receivables (e.g., credit sales, additional charges like interest).
• Note credit entries decrease receivables (e.g., payments, returns, write-offs, contras).
• Evaluate options: only interest charged adds to the owed amount, requiring a debit.

Why C is correct:

• Interest charged on overdue accounts increases the customer's outstanding balance, debited to the control account to reflect higher receivables per double-entry accounting.

Why the others are wrong:

• A. Contra entry offsets debts, reducing receivables and credited to the sales ledger control.
• B. Irrecoverable debt write-off removes uncollectible amounts, reducing receivables and credited to the control.
• D. Sales returns decrease net sales owed, reducing receivables and credited to the control.

Final answer: C