After the cpas have selected particular accounts receivable for confirmation: a. as a control measure, the cpas should carefully list the audited values of all of those accounts before turning the letters over to the client to type and mail. b. it is important that every account selected that has a material balance ultimately be verified by confirmation or the application of alternative procedures; immaterial balances never require any follow-up through alternative procedures. c. all requests for confirmation should be mailed in envelopes bearing the cpa firm's return address and should include a return envelope addressed to the cpa firm. d. all differences between confirmation replies and book values should be reconciled by the cpas, rather than the client.