You are the Office 365 administrator for your company. The company requests that you implement a document collaboration

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You are the Office 365 administrator for your company.
The company requests that you implement a document collaboration and social networking solution that meets the following requirements:
✑ Users must be able to join groups to receive project updates.
✑ Any user must be able to post an event.
You need to implement a solution.
Which solution should you implement?

A. Microsoft SharePoint document libraries
B. Microsoft Yammer
C. Microsoft OneDrive for Business
D. Microsoft SharePoint newsfeeds