Which definition of the term nullify is correct?

a.
to disregard a law that is thought to be unconstitutional

b.
to request a formal ruling by a court on a legal matter

c.
to severe all ties with a political union or government

d.
to submit to the authority of a government agency.

Sir thomas more, venerated in the catholic church as saint thomas more, was an english lawyer, social philosopher, author, statesman, and noted renaissance humanist. he was also a councillor to henry viii, and lord high chancellor of england from october 1529 to 16 may 1532. i found this information on wikipedia