Concept:An error of commission is a clerical mistake where an entry is posted to the wrong account of the same class.
Explanation:Salary account and stationery account are both nominal, or expense, accounts.
Therefore, debiting salary instead of stationery does not violate any accounting principle.
It is simply a wrong selection of account, so it is not an error of principle.
No transaction is omitted, and there is no offsetting mistake present.
This type of mistake is classified as an error of commission.
Answer:A. commission