When designing substantive tests of transactions for sales, the auditor is concerned with the possibility of several types of misstatements. Which of the following is not one of the types of these misstatements?

When designing substantive tests of transactions for sales, the auditor is concerned with the possibility of several types of misstatements. Which of the following is not one of the types of these misstatements?

    a.    Sales being included in the journal for which no shipment was made.
    b.    Sales to related parties, such as officers and subsidiaries.
    c.    Sales recorded more than once.
    d.    Shipments being made to nonexistent customers and recorded as sales.