Enthuware practice test question

[Amit Hetawal]

Hello,
Please advise on below question

  A web application named webmail has a file named folderview.jsp which the user should be able access directly. Which of the following directories may contain this file? 
  
Select 2 correct options 
a  /webmail/jsp   
      
b  /webmail/WEB-INF/jsp   
       
c  /webmail   
        
d  /webmail/web-inf/jsp   
        
e  /webmail/WEB-INF/lib/jsp 
 
  

Answers : A, C

I wonder why D is not a correct answer. And also is WEB-INF case-sensitive ?

Thanks