Analysis. Answer option A is correct.
The Web.config file includes settings specific to an application. The <deny> element is used to deny access to a resource. The users attribute of the <deny> element specifies the user names that are denied access to a resource. Setting this attribute to "?" denies anonymous or unauthorized users from accessing the application.
== What is Web.config==
Web.config is an XML file that consists of a series of settings specific to
an application. Whenever a new Web service project is created in Visual Studio
.Net, the Web.config file is automatically created and added to the project.
It contains a number of empty settings with text explaining each section and
its use.
Answer option B is incorrect. Setting the users attribute to "*" will deny all users from accessing the application. However, Sam wants to restrict only unauthorized users from accessing the application.
Answer options D and C are incorrect. The <allow> element is used to allow access to a resource. The users attribute of the <allow> element specifies the user names that are allowed access to a resource. Setting this attribute to "*" allows all users to access the application and setting it to "?" allows only anonymous users to access the application.