The correct option is A Double entry system
Dual aspect accounting is a concept which assumes that every business transaction will give two effects, i.e. debit and credit. For every debit there will be a credit, and vice versa. Double entry system of accounting is commonly used by all the organizations. Small concerns who are not well versed with double entry system are following the single entry system, in which they maintained only account of debtors and creditors and bank account.