Ben is responsible for a new application with a worldwide user base that will allow users to sign up to access existing data about them. He would like to use a method of authentication that will permit him to verify that users are the correct people to match up with their accounts. How can he validate these users?

Require that they present their Social Security number

Require them to use a federated identity via Google

Require them to use knowledge$-$based authentication

Require them to validate an email sent to the account they signed up with