The email publisher lets support agents who use Case Feed compose and send email messages
to customers. You can customize this publisher to support email templates and attachments. This
component can only be used in organizations that have Case Feed and Email-to-Case enabled.
Ext JS versions less than 3 should not be included on pages that use this component.

A.
apex:pageBlock

B.
apex:define

C.
apex:component

D.
apex:emailPublisher