Which three factors Should be considered before finalizing the number of business unit they need to purchase?

Northern Trail Outfitters (NTO) is migrating from a series of local legacy email automation tools to a single global Marketing Cloud instance to leverage its multi-channels abilities as well as native Salesforce Connector to their global Sales Cloud instance.

Which three factors Should be considered before finalizing the number of business unit they need to purchase? (Choose 3 answers)
A . Number of brands/geographies which NTO operates
B . Number of Sales Cloud sandboxes
C . If testing/development business unit($) is required
D . If data/content needs to be segregated between brands/geographies
E . Number of Marketing Cloud users.

Answer: A,B,C