Which accounting concept is used in the following accounting treatment?

"A customer saw a bed in 2007 and said he might buy it. He called in 2008 and ask for the bed to be delivered. The item was not treated as a sale in 2007 but was treated as a sale in 2008".

Select one:

• a. Money measurement
• b. Accrual
• c. Realization
• d. Historic cost