How many communities can you have in Salesforce?

Answer options:

A.100
B.50
C.300
D.500

Correct Answer: A 
In Salesforce, you can have up to 100 communities. The active, inactive, and preview communities in addition to lightning platform sites count against this limit. 
Reference:

https://help.salesforce.com/articleView?id=users_license_types_communities.htm&type=5