The correct answer is option 'A', Part XX.

Explanation:
The Constitution of India is the supreme law of the country, and it provides for its amendment to meet the changing needs of society. The amendment process is laid out in Part XX of the Constitution of India.

1. Part XX:
Part XX of the Constitution of India deals with the amendment process. It consists of only one article, Article 368, which outlines the procedure for amending the Constitution.

2. Article 368:
Article 368 provides the detailed procedure for amending the Constitution. It specifies the requirement for passing an amendment, the different types of amendments, and the role of the President in the amendment process.

3. Procedure for Amendment:
According to Article 368, an amendment to the Constitution can be initiated only by introducing a bill in either House of Parliament. The bill must be passed in each House by a special majority, which means a majority of the total membership of that House and a majority of not less than two-thirds of the members present and voting.

4. Types of Amendments:
Article 368 also distinguishes between two types of amendments:
- Amendments requiring a simple majority: Some provisions of the Constitution can be amended by a simple majority, which means a majority of the members present and voting. These amendments do not need to be passed by a special majority.
- Amendments requiring a special majority: Most provisions of the Constitution can be amended only by a special majority, as mentioned earlier.

5. Role of the President:
After a bill for amendment is passed by both Houses of Parliament, it is presented to the President for his/her assent. The President can either give his/her assent or withhold it. The President does not have the power to return the bill for reconsideration, and his/her assent is final.

In conclusion, Part XX of the Constitution of India deals with the amendment process, and Article 368 provides the detailed procedure for amending the Constitution.