Which data transformation should be used to determine if a subscription is new or a renewal?

An Einstein Analytics Consultant is working with a subscriptions based company to build a dashboard to understand customer renewals. Each subscription is captured as a Closed Won Opportunity within Salesforce Unfortunately the Opportunity record does not specify whether it is a renewal or a net new subscription.

Which data transformation should be used to determine if a subscription is new or a renewal?
A . ComputeRelative
B . ComputeExpression
C . Augment
D . flatten

Answer: D