Which of the following is true about Roll-up summary fields?

The assertion that roll-up summary fields are read-only is indeed accurate. Roll-up summary fields are calculated fields that summarize data from related child records into a parent record in a master-detail relationship. This comes into play when you need to aggregate data from multiple children, such as counting the number of related records or calculating the average of a numerical field.

These fields automatically update as child records are created or modified, and they cannot be directly edited by users, emphasizing their read-only nature. This ensures the integrity of the summary data; users can see the aggregated information from the child records, but cannot alter it manually, which is consistent with the way data integrity is maintained in relationships.

In contrast, while roll-up summary fields can perform functions like SUM, MIN, MAX, and AVG, their results will be displayed on the parent record rather than on the child. They can only be configured on the parent side of a master-detail relationship, not a lookup. Thus, the distinguishing feature of their read-only status aligns with the purpose of maintaining consistent and accurate data representation from child to parent.