Doubt in sessions from Hanumant Deskhmukh book

[deepti bellubbi]

I am a bit confused about the answer to this question. Please advise.

Which of the following methods will be invoked on a session attribute that
implements appropriate interfaces when the session is invalidated? (Select one)
a sessionDestroyed of HttpSessionListener
b attributeRemoved of HttpSessionAttributeListener
c valueUnbound of HttpSessionBindingListener
d sessionWillPassivate of HttpSessionActivationListener

I think the answer should be "a" since the question clearly says invalidate, however the books says the answer is "C".

[Pham Hoai Van]

The question states that: "methods will be invoked on a session attribute"
And HttpSessionBindingListener is the only interface that an attribute can implement so C is obvious.

[deepti bellubbi]

Thanks..confusion solved