Q) What should a system administrator consider when deleting a custom field? (Select 3)
a. Existing field values must be transferred to a new custom field
b. Field values should be archived before a field is deleted
c. Fields used in a workflow and assignment rules cannot be deleted
d. Deleted fields and values can be restored from the recycle bin within 15 days
e. Fields must be remove from page layouts after being deleted

Which all 3 are correct answer because I am getting different answers on different websites and posts?

i'm very much confused about preparing 1st salesforce exam ( ADM-201). i need study material as well as guidance for exam.