In CORS, the purpose of a preflight request is to __________ (Select all that apply).
1. Provide a method of authentication before secure data is sent.
2. Check to see if the protocol is understood
3. Block the request from the server permanently
4. Determine the location of server-side resources.
5. Determine whether the server will accept the actual request before sending it.
6. None of the answers are correct
7. Send additional data that is too large for a single request.