Concept:An error of principle occurs when a transaction is recorded in the wrong class or type of account, violating fundamental accounting principles.
Explanation:An error of principle is a procedural mistake where the correct value is recorded, but it is placed in an incorrect category of account.
For example, treating a revenue expense as a capital expense is an error of principle.
Option A states that an entry has been made on the wrong class of account. This matches the exact definition.
Option B describes an error of omission, where a transaction has been completely left out.
Option C describes an error of commission, where the entry is made on the wrong side of the two accounts concerned.
Option D also describes an error of commission, where both accounts are entered with the wrong amount.
Only option A correctly identifies an error of principle.
Answer:A. an entry has been made on the wrong class of account