Explanations:The integration of Sikkim into the Indian Union is a significant historical event that took place in 1975. Prior to this, Sikkim was a protectorate under Indian control, with a degree of autonomy. The Chogyal (ruler) of Sikkim, Palden Thondup Namgyal, was the head of state, and the country had a unique political status that was neither a state nor a union territory of India.
In 1973, a political crisis erupted in Sikkim, leading to the formation of a new government under Kazi Lhendup Dorji. The new government sought to end the protectorate status and integrate Sikkim fully into India. A referendum was held in 1975, in which the majority of the Sikkimese people voted in favor of joining India. Following the referendum, the Indian Parliament passed the 35th Amendment to the Constitution of India, which officially made Sikkim the 22nd state of India on May 16, 1975.
It is important to understand the historical context of Sikkim's integration into India. The protectorate status of Sikkim was established in 1950, when the Chogyal signed an agreement with India, which gave India control over Sikkim's defense, foreign affairs, and communications. However, Sikkim retained its own government and a degree of autonomy. The integration in 1975 marked the end of this protectorate status and the beginning of Sikkim's full integration into the Indian Union.
Other states mentioned in the options, such as Goa, Manipur, and Tripura, have their own distinct historical timelines of integration into India. Goa was annexed by India in 1961, following a military operation known as Operation Vijay. Manipur and Tripura were both integrated into India in 1949, when their rulers signed the Instrument of Accession, which brought them under the Indian Union.
Understanding the specific historical events and timelines of each state's integration into India is crucial for correctly identifying the year and state in questions like this. The integration of Sikkim in 1975 is a unique event that stands out in the history of Indian states, and it is important to remember the context and the process that led to this integration.