Assuming the tag library in the exhibit is imported with the prefix forum， which custom tag invocation produces a translation error in a JSP page？（）

单项选择题Whichthe securitymechanismusestheconceptofarealm？（）

A. authorization
B. data integrity
C. confidentiality
D. authentication

单项选择题Whichthe basicauthenticationtypeisoptionalforaJ2EE1.4compliantwebcontainer？（）

A. HTTP Basic Authentication
B. Form Based Authentication
C. HTTP Digest Authentication
D. HTTPS Client Authentication

单项选择题Whenaddingaelementtoawebapplicationdeploymentdescriptor，theinclusionofwhichsub-elementrequiresthedefinitionofanerrorpage（）？

A. <realm-name> 
B. <auth-metod> 
C. <auth-constraint> 
D. <form-login-config> 
E. <user-data-constaint>

单项选择题Whichsecuritymechanismcanbedirectedthroughtheelementinawebdeploymentdescriptor（）？

A. authorization
B. data integrity
C. confidentiality
D. authentication

多项选择题A Company.com developer has created a web application that includes a servlet for each use case in the application. These servlets have become rather difficult to maintain because the request processing methods have become very large. There is also common processing code in many servlets because these use cases are very similar.  Which two design patterns can be used together to refactor and simplify this web application？ （）

A. Proxy
B. View Helper
C. Front Controller
D. Session Façade
E. Business Delegate
F. Model-View-Controller