Choice "C" is correct. The auditor should view related party transactions within the framework of existing pronouncements, placing primary emphasis on the adequacy of disclosure.
Choice "b" is incorrect. Since related party transactions are (by definition) not considered to be at arm's-length, the auditor generally does not ascertain the rights and obligations of the related parties.
Choice "a" is incorrect. The auditor generally does not confirm the existence of the related parties.
Choice "d" is incorrect. Since related party transactions are (by definition) not considered to be at arm's-length, the auditor generally does not verify the valuation of the related party transactions.