E-mail managers are locally installed e-mail softwares. They are programs that allow you to set up one or several email accounts, store incoming messages, send, notify new emails and do all the connection between your e-mail account and the recipient's email.
1. ughhhh not entirely sure but B, 2. again not entirely sure should be B as well and finally 3.is D remember these are not always the answer just most likely what one person thinks