The correct answer is B. Attachment.
An attachment is a file that is sent along with an email message. When you send an email with an attachment, the recipient will receive the email message and the attached file. The recipient can then open the attached file to view its contents.
Inclusion is a feature in some email programs that allows you to include a copy of an existing email message in a new email message. When you include an email message, the recipient will receive the new email message and a copy of the original email message. The recipient can then view the original email message to see the context of the new email message.
Reply is a feature in email programs that allows you to send a response to an existing email message. When you reply to an email message, the recipient will receive a new email message that contains your response. The recipient can then view your response to see how you have responded to their original email message.
Forward is a feature in email programs that allows you to send an existing email message to another recipient. When you forward an email message, the recipient will receive a new email message that contains the original email message. The recipient can then view the original email message to see the contents of the message.
In this case, the user wants to send a PowerPoint show to another teacher. The best way to do this is to add the PowerPoint show as an attachment to the email message. This will allow the recipient to open the PowerPoint show and view its contents.