Which of the statements is/are true for data validation? 

Answer options:

A. Data Validation can enforce data integrity as well as make a field required in the page layout
B. Data Validation can prevent duplication of records
C. Data Validation run on the client machine after the user clicks the Save button
D. Data Validation rules are not enforced when using API & import operations
E. Validation rules can be activated / deactivated by the user

AB