Which statement is true?

Given the fragment from Java EE deployment descriptor:
341. <error-page>
342. <exception-type>java.lang.Throwable</exception-type>

343. <location>/mainError.jsp</location>
344. </error-page>
345. <error-page>
346. <exception-type>java.lang.ClassCastException</exception-type>
347. <location>/castError.jsp</location>
348. </error-page>
If the web application associated with the fragment above throws a ClassCastException.
Which statement is true?

A.
The deployment descriptor is invalid.

B.
The container invokes mainError.jsp

C.
The container invokes castError.jsp

D.
Neither mainError.jsp nor castError.jsp is invoked.