Which two solutions prevent a formula field from being referenced by a Roll-Up Summary Field?

A Roll-Up Summary Field (RUSF) on a master object cannot reference a formula field on the detail object if that formula has certain characteristics. Specifically, a formula field is ineligible for roll-up aggregation if it includes a cross-object field reference (i.e., it references fields on an object other than the detail record itself). This is because the roll-up calculation is confined to the master-detail relationship.

Furthermore, formula fields that use dynamic date/time functions, such as NOW() or TODAY(), are also prohibited. The values from these functions change automatically over time without a DML event on the record, which is incompatible with the trigger-based recalculation mechanism of RUSFs.

A. A cross-object workflow updating a source field does not inherently disqualify the formula. The validity depends on the formula's content, not how its inputs are updated.

C. The CASE() function is a standard logical function used for conditional logic and is fully supported in formula fields that are eligible for roll-up summaries.

1. Salesforce Help Documentation, "Roll-Up Summary Field": Under the section "Notes on creating roll-up summary fields," the documentation explicitly states, "You can't use...cross-object formula fields...in the field to be aggregated column." This directly supports option B.

2. Salesforce Help Documentation, "Considerations for Roll-Up Summary Fields": This document clarifies the limitations, stating, "A roll-up summary field can’t reference a formula field that references a dynamic date function, such as DATEVALUE, NOW, or TODAY." This directly supports option D.

3. Salesforce Help Documentation, "Formula Operators and Functions": The description for the NOW() function explains that it returns the current date and time, which is a dynamically changing value. This inherent volatility is the reason it cannot be used in RUSFs, which require a stable value that only changes upon a record save.