What must occur before a transaction can be captured?

Before a transaction can be captured, it is essential for the transaction to be authorized. Authorization is a critical step in the payment process where the financial institution verifies that the cardholder has sufficient funds or credit available to complete the transaction. This process helps ensure that the transaction is legitimate and reduces the risk of fraud.

Once a transaction is authorized, capturing can occur, which means that the payment is processed, and the funds are transferred from the cardholder's account to the merchant’s account. Without this prior authorization, capturing a transaction would not be possible, as there is no guarantee of payment.

The other choices do not represent necessary prerequisites for capturing a transaction. Shipping the transaction, printing a receipt, or contacting the customer may be important steps in the overall transaction lifecycle or customer service process, but they do not relate directly to the financial aspect of capturing payment. Thus, authorization stands out as the pivotal requirement before a transaction can be captured.