Choice "B" is correct. Confirmations are among the most reliable types of evidence, as they constitute external evidence sent directly to the auditor.
Choice "a" is incorrect. Inquiries provide oral evidence, which is less reliable than confirmations.
Choice "d" is incorrect. Analytical procedures provide the auditor with direct personal knowledge, but because these procedures often are based on internal accounting data, the evidence obtained is not as reliable as that obtained from confirmations.
Choice "c" is incorrect. Review of audit procedures from the previous year does not provide appropriate audit evidence regarding the current year's financial statements.