Final answer:
When Alton replies to Chan's email using the "Reply" feature, his message will be sent back to Chan with Alton's added text and typically the original email text included. However, the original attachment will not be included unless manually reattached by Alton.
Step-by-step explanation:
When Alton uses the "Reply" feature to write back to Chan, the content of Alton's reply will include the text that he writes in his response. The original email that Chan sent will typically be included below Alton's reply, often indicated by a special character such as a greater-than sign (>) or included within a blockquote format. It's important to note that the attachment that Chan originally sent will not be automatically included in Alton's reply. If Alton wants to include the original attachment, he would have to manually reattach it. Most email clients and services follow this approach to prevent the unnecessary duplication of attachments.