Feels more like a segment to me? "Segments let you group your customers based on demographic, transactional, or behavioral attributes." https://docs.microsoft.com/en-us/dynamics365/customer-insights/audience-insights/segments

Measure is the correct one because segment allows you to GROUP YOUR CUSTOMERS while measure helps you calculate the total sales by those groups.

Segment: Segments are used to group data based on specific criteria or attributes. In this case, you want to segment your data based on age groups, which makes "segment" the correct choice.

C. You can create segments in CS Insights: https://learn.microsoft.com/en-us/dynamics365/customer-insights/segments?tabs=b2c

C. segment To analyze product sales trends by age group in Dynamics 365 Customer Service Insights, you would need to define a segment. A segment is a grouping of customers based on common attributes, such as age group in this case. Once you define the segment, you can use it to analyze measures, such as product sales, for the specific age groups. Activities represent interactions between customers and agents, measures are the metrics being analyzed, and members are individual customers or cases within a segment.

Defo Segment

customer service insights is not the same as customer insight (provided in the link)

It's measure

Segment is require. We dont need to calculate anything. (avg, sum, etc) We have to create many group.