Answer: M. The Judicial branch determined whether or not laws were to be executed.
Explanation: Marshall is making a point that it's up to the courts not to politicians to decide what is and what isn't constitutional. Prior to the Supreme Court's landmark ruling in Marbury v. Madison 1803, the judicial branch of government was extraordinarily weak. It could interpret the law but did not have the final say on whether a specific law was constitutional or not.
