Final answer:
In the Debug logs, Workflow rules can be tracked. Roll-up Summary and formula field calculations are computed behind the scenes and are not directly traceable in the logs, whereas Assignment rules are not clearly traced as Workflow rules.
Step-by-step explanation:
Among the options provided, Workflow rules can be tracked in the Debug logs. A debug log records database operations, system processes, and errors that occur when executing a transaction or while running unit tests. It is used primarily by developers to track the execution of code and to understand how data and operations change at different points in the execution flow.
Roll-up Summary field calculations and formula field calculations are not directly trackable with Debug logs as these are calculated by the system behind the scenes. Assignment rules, which are used to automatically assign records to users or queues based on certain criteria, can sometimes be inferred from debug logs, but they are not as directly traceable as workflow rules.