Based on the provided procedure, determine the most likely audit approach (combined or substantive) that an auditor has selected for the specific cycle. \begin{tabular}{|l|l|} \hline rroceaures & or supstantive) \\ \hline After gaining an understanding of internal controls in the sales & \\ cycle, the auditor decided to select a sample of customers and \\ verify that for each customer a credit review form was completed \\ and the form was signed by the manager. \end{tabular}