The correct answer is option 'D', the Government of India Act 1935.

Explanation:
The Government of India Act 1935 was a significant legislation passed by the British Parliament that introduced provincial autonomy in India. This act aimed to provide a framework for the governance of British India, and it laid the foundation for a more democratic and representative system of government.

The key provisions and features of the Government of India Act 1935 that introduced provincial autonomy are as follows:

1. Provincial Autonomy: The act provided for the establishment of provincial governments with legislative and executive powers. The provinces were granted autonomy in a wide range of areas, including education, health, agriculture, local government, and public works.

2. Provincial Legislature: The act introduced bicameral legislatures at the provincial level, consisting of an upper house (Council of State) and a lower house (Legislative Assembly). Members of the Legislative Assembly were to be elected by the people, providing them with a voice in the legislative process.

3. Responsible Government: The act introduced the concept of responsible government at the provincial level. The Governor was to act on the advice of the ministers who were responsible to the provincial legislatures.

4. Diarchy: The act established a diarchy system at the provincial level, dividing the subjects of administration into two categories - reserved and transferred. The reserved subjects were to be administered by the Governor and his executive council, while the transferred subjects were to be administered by the ministers responsible to the legislature.

5. Federal Provisions: The act also made provisions for the establishment of a federal government in India, but these provisions were never implemented due to various reasons.

Overall, the Government of India Act 1935 marked a significant step towards granting greater autonomy to the provinces in India. It provided for elected legislatures, responsible government, and the transfer of powers to the provinces in various areas of administration. However, it should be noted that the act did not satisfy the demands of the Indian nationalists for complete independence and self-rule, and it ultimately paved the way for further constitutional reforms and the eventual independence of India.

Government of India Act of 1935 marked the second milestone towards a completely responsible government in India. It ended Diarchy and provided the establishment of All India Federation. This act served some useful purposes by the experiment of provincial autonomy, thus we can say that the Government of India Act 1935 marks a point of no return in the history of constitutional development in India.