单项选择题
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？（）
A.A B.B C.C D.D E.E
单项选择题 Whichthe securitymechanismusestheconceptofarealm？（）
单项选择题 Whichthe basicauthenticationtypeisoptionalforaJ2EE1.4compliantwebcontainer？（）
单项选择题 Whenaddingaelementtoawebapplicationdeploymentdescriptor，theinclusionofwhichsub-elementrequiresthedefinitionofanerrorpage（）？
