What would declaring an agency’s regulations unconstitutional be an example of?

Question

Congressional oversight of the bureaucracy.
Presidential oversight of the bureaucracy.
Media oversight of the bureaucracy.
Judicial oversight of the bureaucracy.

Answer 1

Only a federal judge (or panel of judges) can officially declair regulations unconstitutional. (I think that may are unconstitutional, but what I think doesn't count.)

Now you have enough info to answer your question.