Which are the two data sources that must be incorporated inside Contact Builder?

An entertainment company is hosting events across the country in different venues. They want to use Contact Builder to feed Journey Builder. Contact who enter a journey will go through a decision split based on the type of event. The journey will send a series of emails and one of them will contain the venue details dynamically populated with AMP script.

The Company collects the following information:

– Customer data (email address, first name, last name…).

– Event registration (email address, event ID, event name, event type, venue ID…).

– Venue details (venue ID, venue name, venue address…).

– Payment details (email address, event ID, total paid…).

The Company does not want to link everything in Contact Builder.

Which are the two data sources that must be incorporated inside Contact Builder? (Choose two.)
A . Event Registration
B . Customer Data
C . Venue Details
D . Payment Details