The correct option is A Commission
Errors of commission are the errors that are committed due to wrong posting of transactions, wrong totaling or balancing of the accounts, wrong casting of the subsidiary books, or wrong recording of the amount in the books of original entry, etc. Rs. 5,100 paid to Sonu as salary for the month of December 2008 wad debited to his A/c. This constitutes an error of commission. Such an error by definition is of clerical nature and most of the errors of commission affect the trial balance.