For amending the rigid parts of the Indian Constitution, the provision has been made under which article?

Article 368

The correct answer is Option 4 - Article 368

There are many articles in the Constitution, which mention that these articles can be amended by a simple law of the Parliament. No special procedure for amendment is required in such cases and there is no difference at all between an amendment and an ordinary law. These parts of the Constitution are very flexible. Read carefully the following text of some articles of the Constitution. In both these articles, the wording ‘by law’ indicates that these articles can be modified by the Parliament without recourse to the procedure laid down in Article 368. Many other articles of the Constitution can be modified by the Parliament in this simple manner.
Article 2: Parliament may by law admit into the union …..new states….
Article 3: Parliament may by law… b) increase the area of any state….

For amending the remaining parts of the Constitution, provision has been made in Article 368 of the Constitution. In this article, there are two methods of amending the Constitution and they apply to two different sets of articles of the Constitution. One method is that amendment can be made by special majority of the two houses of the Parliament. The other method is more difficult: it requires special majority of the Parliament and consent of half of the State legislatures. Note that all amendments to the Constitution are initiated only in the Parliament. Besides the special majority in the Parliament no outside agency— —like a constitution commission or a separate body—is required for amending the Constitution.