A web application is unable to authenticate customers so they can access their bills. The server administrator has tested the LDAP query but is not receiving results. Which of the following is the NEXT step the server administrator should take to correct the problem? 

Answer options:

A. Check port 636 to see if it is being blocked.
B. Change service port 636 to port 389.
C. Restart the web server.
D. Verify the browser is using port 443.

A