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

 A formula field cannot be referenced by a roll-up summary field if it contains a cross-object field reference or a time-based function. A cross-object field reference is a reference to a field from a different object, such as Account. Name on a Contact object. A time-based function is a function that returns the current date or time, such as NOW() or TODAY(). Option A and C do not prevent a formula field from being referenced by a roll-up summary field.