The correct option is A.
The federal government is divided into three parts, which are the executive, the legislative and the judiciary. The executive is made up of the president and his workers, the legislative is made up of the senate and the house of representative while the judiciary is made up of the supreme court and the lower courts. The legislative has been empowered by the constitution to ratify amendments of the constitution. An amendment usually become ratified after two third of the senate and house of representative have approve of its proposal.