You have an Exchange Server 2010 organization named contoso.com. The organization contains two Client Access servers named CAS1 and CAS2 that are in a Client Accessserver array. All internal and external users connect to their mailboxes by using mail.contoso.com. You need to install a certificate on the Client Access servers to meet the following requirements：.Support 500 client computers that are not joined to the Active Directory domain .Support clients that use Microsoft Office Outlook in Cached Exchange Mode， Autodiscover， andExchange ActiveSync .Minimize client and user support costs What should you do？（）
- AFrom a trusted third-party certification authority （CA）， generate a certificate request that contains the mail.contoso.com and Autodiscover names.
- BFrom a trusted third-party certification authority （CA）， generate a certificate request that contains the CAS1.contoso.com and CAS2.contoso.com names.
- CFrom an internal Active Directory-integrated certification authority （CA）， generate a certificate request that contains the mail.contoso.com and Autodiscover names.
- DFrom an internal Active Directory-integrated certification authority （CA）， generate a certificate request that contains the CAS1.contoso.com and CAS2.contoso.com names.