During the course of an audit, the auditor examines a wide variety of documentation. Listed below are some forms of documentary evidence and the sources from which they are obtained. FORMS OF DOCUMENTARY EVIDENCE USED BY THE AUDITOR AND THE SOURCES OF THAT EVIDENCE (a) Bank statement sent directly to the auditor by the bank. (b) Creditor monthly statement obtained from client's file. (c) Vouchers in client's unpaid voucher file. (d) Duplicate sales invoices in filled order file. (e) Time tickets filed in payroll department. (1) Credit memo in customer's file. (g) Material requisitions filed in storeroom. (h) Bank statement in client's file. (i) Paid checks returned with bank statement in (a) above. 6) Memo in customer file from treasurer authorizing the write off of the account. REQUIRED: (1) Classify the items of evidence above into one of the four categories listed below. (a) Evidence prepared externally sent directly to the auditor. (b) Evidence prepared externally but held by the client. (c) Evidence prepared internally but validated by an external party. Evidence prepared internally and held by the client. Discuss the reliability of the four sources of evidence listed in (1) above. (2)