Concept:A set off in control accounts is another name for a contra entry, which cancels out related balances.
Explanation:Set off occurs when the same person is both a debtor and a creditor of the business.
The business reduces the amount owed to that person against the amount the person owes the business.
This transaction is recorded as a contra entry in the control accounts.
It affects both the sales ledger control account and the purchases ledger control account.
The net balance is then shown instead of the full amounts.
Therefore, in control account work, "set off" is also called a contra entry.
Answer:B. contra entry