Your company named Contoso， Ltd. has a Web server named WEB1.   The Web server runs Windows Server 2008. The fully qualified domain name of WEB1 is web1.contoso.com. The public DNS server has an alias record named owa.contoso.com that maps to web1.contoso.com. Users access WEB1 from the Internet by using http：//owa.contoso.com.  The new company security policy states that the owa.contoso.com site must be available for Internet users only through secure HTTP （HTTPS） protocol. The security policy also states that users must not get security warnings when they connect to the site.  You need to request a certificate from a public certification authority （CA）. Which Common Name should you use？（）