Which feature should a system administrator use to display the amount of all closed won opportunities in account records?

Using roll-up summary fields is the appropriate method for displaying the total amount of all closed-won opportunities directly on the account records. Roll-up summary fields allow you to aggregate values from related records, summarizing data from child records (in this case, opportunities) and displaying that data on their parent record (the account).

Roll-up summary fields are specifically designed for scenarios like this, where calculations need to be performed from child records to present an aggregate value on the parent record. The feature supports operations such as SUM, COUNT, MIN, and MAX, enabling the administrator to easily calculate the total amount of all closed-won opportunities tied to an account.

Other options may offer data manipulation or automation but do not provide the direct aggregation functionality required for this use case. For instance, while calculated columns can show data, they are not as straightforward in summing values from related records like roll-up summary fields. Cross-object formula fields can reference related records but do not aggregate data. Workflow rules with field updates are primarily aimed at automating changes of values based on specific triggers and do not inherently support the kind of summary calculations required here. Therefore, for displaying the total of closed-won opportunities directly on the account record, roll-up summary fields is the most efficient