What should a consultant recommend as a unique identifier for each subscriber?

Northern Trail Outfitters (NTO) plans on sending SMS and push notifications together with emails as part of a new customer onboarding journey.

What should a consultant recommend as a unique identifier for each subscriber?
A . A common field like Physical Address for Contact Key.
B. A number field such as subscriber’s phone number for Contact Key.
C. An email address for Contact Key.
D. A GUID or another generated ID for Contact Key.

View Answer

Answer: B