The question asks for the Article of the Constitution under which the Inter-State Council has been constituted. Article 360 deals with Financial Emergency. Article 263 deals with the provisions relating to an Inter-State Council, empowering the President to establish such a Council if it appears to him that the public interests would be served thereby. Article 365 deals with the effect of failure to comply with, or to give effect to, directions given by the Union Government. Article 368 deals with the power of Parliament to amend the Constitution and the procedure for amendment. Therefore, Article 263 is the correct answer.