What occurs if you change the datatype of a custom field that is set as an external ID, choosing a data type other than text, number, or email?
A. The external ID referenced is not affected
B. A warning message is sent every time the record is accessed
C. Validation rules prevent this type of change
D. The field no longer acts as an external ID
Answer: D. The field no longer acts as an external ID
Any field type other than text, number or email cannot be uniquely identified, hence the inability to continue as an external ID.