What does it mean to say that a term cannot be $$bargained to impasse$?$

Group of answer choices

A $$bargained to impasse$$ term means that a particular term is legislatively mandated$$for example, the duty to bargain in good faith$$and so cannot be changed at the negotiating table.

A $$bargained to impasse$$ term is one that negotiating parties use to indicate that they do not wish to pursue a particular negotiating item.

A $$bargained to impasse$$ term refers to a series of particular issues that, while bargainable, cannot be the basis for industrial action$$that is$,$ the status quo must prevail in the event that the parties cannot agree.

A $$bargained to impasse$$ term is negotiated separately from the main issues under consideration.