The correct answer is C. Commission.
A commission error is an error in which an item is recorded in the wrong account. In this case, the repairs of second hand machinery purchased should be recorded in the asset account “Machinery”, but it has been recorded in the expense account “Repairs”.
An omission error is an error in which an item is not recorded at all. For example, if a purchase is made but not recorded in the accounting records, this would be an omission error.
A compensating error is an error that cancels out another error. For example, if a $100 expense is recorded twice, this would be a compensating error because the total effect on the financial statements would be zero.
A principle error is an error in which an item is recorded incorrectly according to the accounting principles. For example, if a sale is recorded at the wrong price, this would be a principle error.
I hope this helps!