Correct Answer: (c) 1972
Note: In 1957, the Government of India appointed Justice N. Rajagopala Ayyangar Committee to examine the question of revision of the Patent Law and advise government accordingly. On the recommendation of this committee, the Patent Bill was introduced in the Lok Sabha on 21 September, 1965, which however lapsed. In 1967, again an amended bill was introduced which was referred to a joint Parliamentary Committee and on the final recommendation of the Committee, the Patents Act, 1970 was passed. This Act repealed and replaced the 1911 Act so far as the patents law was concerned. Most of the provisions of the 1970 Act were brought into force on 20th April, 1972 with publication of the Patent Rules, 1972.