Mark works as a Programmer for InfoTech Inc. He develops a deployment descriptor code that contains three valid
<security-constraint> elements.
All of them constraining a Web resource Res1, the
<auth-constraint> sub-element of the <security-constraint> elements are as follows.
<auth-constraint>Admin</auth-constraint>
<auth-constraint>Manager</auth-constraint>
<auth-constraint/>
Which of the following can access the resource Res1?