Which two actions should UC take to prevent unauthorised form submissions during the self-registration process?

Universal containers (UC) is concerned that having a self-registration page will provide a means for "bots" or unintended audiences to create user records, thereby consuming licences and adding dirty data .

Which two actions should UC take to prevent unauthorised form submissions during the self-registration process? Choose 2 answers
A . Use open-ended security questions and complex password requirements
B. Primarily use lookup and picklist fields on the self registration page.
C. Require a captcha at the end of the self-registration process.
D. Use hidden fields populated via java script events in the self-registration page.

Answer: C,D