Coordination of the direction of testing can increase the efficiency of audit tests. If an auditor has adopted the strategy of testing asset and expense account balances directly for overstatement and liability and revenue balances directly for understatement, how would planning the audit tests for accounts payable be structured? 

a. Using the activity format, indicate the direction of testing for the components of accounts payable. 

b. In general, how would an auditor test a liability balance, such as accounts payable, directly for understatement? 

c. How would the accounts payable ending balance be indirectly tested for over-statement?