Which two actions should you recommend?

You are creating a plan to add new functionality to an existing application in a SharePoint 2010 farm. The original
application uses a site definition for site creation. Your plan needs to specify how to deploy the new functionality
to meet all these requirements:
The new functionality must include a Web Part that displays sales statistics and graphs.
.New sites that use the site definition must contain the new Web Part.
.The new functionality must be added to several existing sites.
.Deploying the new functionality must not disrupt the current functionality of the sites.

Which two actions should you recommend? (Each correct answer presents part of the solution. Choose two.)

A.
Build the new Web Part into a feature and deploy it to the farm.
Activate the feature on all the existing sites that require the new functionality.

B.
Create a new site template that includes the new Web Part.
Use this template to add the new functionality to all sites that require it.

C.
Create a new site definition that includes the feature.
Regenerate the existing sites that require the new functionality using this site definition.

D.
Create a new feature containing the Web Part.
Staple the feature to the site definition that was used to create the existing sites.