You have a legacy application that needs to send email to employees. The legacy application runs on a
client computer.
The legacy application must send email by using IMAP through Exchange Online.
You need to identify the correct host name and port information.
Which settings should you use?

A.
Imap.office365.com and port 993

B.
Imap.office365.com and port 143

C.
Outlook.office365.com and port 993

D.
Outlook.office365.com and port 143

Explanation:
For Office 365 for business, use the following settings.
IMAP4
outlook.office365.com
993 implicit Use POP or IMAP to connect to Office 365 for business or Microsoft Exchange accounts
https://support.office.com/en-US/Article/Use-POP-or-IMAP-to-connect-to-Office-365-for-business-orMicrosoft-Exchange-accounts-44f951cc-2041-47ed-b674-506889ca9d8b