Trupti,
Definitely Hidden form fields is also a correct option for the question.
[
Actually the question,should have been read as,
"Identify the techniques that can be used to implement 'sessions' if the client browser does not support cookies and
a) No work needs to be done by the
servlet developer
b) Secure way of maintaing sessions
]
The question is actually based on the Servlets Specification. And in the Servlets specification,hidden form fields is not given as an option of maintaining Sessions.
HTH