Which are true about Trialforce Email Branding?

Which are true about Trialforce Email Branding?
A . It is available only in Unlimited, Enterprise and Developer Editions
B . It allows you to modify system-generated emails so that they appear to come from your company rather than from Salesforce.com.
C . Trialforce Email Branding is automatically enabled for existing partners with Trialforce and when a new partner request Trialforce.
D . Trialforce Email Branding only applies to users who sign up for your application through Trialforce.

Answer: B,D