Which statement regarding alternate keys is true?
A. You can define only one alternate key per entity.
B. Alternate keys are enforced when creating records through the user interface, and during data imports.
C. You can use date and time fields as part of an alternate key.
D. Alternate keys provide a warning if there is a matching record, but still allow the record to be saved.
Thats wrong. Correct answer is “C”
https://docs.microsoft.com/en-US/dynamics365/customer-engagement/developer/define-alternate-keys-entity#create-alternate-keys
B