The expenses process requires verification of hotel, flight and car rental receipts to be handled by different teams. Verification of each type of invoice is done through different external processes. A request can include flight invoices, hotel invoices, car rental invoices or any combination of the three types. Based on the types of invoices, the process decides which external process to call. After verification of invoices, the process proceeds to pay the expense. Which option illustrates the pattern on how to model these requirements?