A.Requireemployeestoaccesse-mailonlyoverconnectionsthatuseSSL
B.PlaceExchangemailboxstoresonNTFSvolumes.UseEncryptingFileSystem（EFS）toencryptthestores
C.Usetheinternalcertificationauthority（CA）toissuecertificatestoallemployees.Requireemployeestodigitallysignoutbounde-mail
D.Usetheinternalcertificationauthority（CA）toissuecertificatestoallemployeesandvendors.InstructemployeesandvendorstousesecureMIMEtoencryptalle-mailsentbetweenthem
参考答案：C
