Debit balances represent expenses and assets in trial balance

Steps:

• Identify trial balance structure: debit column for assets, expenses; credit for liabilities, incomes, contra accounts.
• Classify each option by account type: expenses debit, incomes/reductions credit.
• Check carriage inwards as direct expense on purchases.
• Confirm others as credit balances.

Why A is correct:

• Carriage inwards is a trading expense, debited per double-entry rules for costs incurred.

Why the others are wrong:

• B: Discounts received is income, credited to reduce expenses.
• C: Provision for doubtful debts is a contra-asset, credited against receivables.
• D: Purchases returns reduces net purchases, credited as contra-expense.

Final answer: A