For each of the following service departments, select the activity base listed that is most appropriate for charging service expenses to responsible units. Activity bases to choose from: Number of employees trained Number of payroll checks Number of sales invoices Number of computers Number of conference attendees Number of travel claims Number of purchase requisitions Number of cell phone minutes used Service Department Activity Base a. Accounts Receivable b. Central Purchasing c. Computer Support d. Conferences e. Employee Travel f. Payroll Accounting g. Telecommunications h. Training