The credit side of the Trial Balance was £11,200 lower than the debit side. The difference was placed in suspense. The correction of which of the following errors will reduce the Suspense account balance:

(a) A cash sale of £3,400 has been posted as £4,300

(b) A credit sale of £2,150 has not been posted to the customer

(c) Stationery acquired on credit terms for £340 has been recorded in the Purchases Journal

(d) A credit note for £900 from a supplier has not been entered in Returns Outwards Day Book