問題文
A new policy requires a referral source whenever a record is first created. Records created before the policy must remain editable without a referral source. Which element in the validation rule formula achieves this?
選択肢
- PRIORVALUE on the referral source field, which returns blank for new records and therefore identifies them.
- Mark the referral source field as universally required, which then applies from the day the policy starts.
- ISCHANGED on the referral source field, so that the rule applies only when a user changes that field, which keeps historical records editable because their referral source is never touched.
- ISNEW, so that the condition is evaluated only while the record is being created.