Task: Question Answering
Input (English): Passage: Three princely states bordering India—Nepal, Bhutan and Sikkim—were not integrated into the Republic of India in the period between 1947 and 1950. Nepal had been recognised by the British and the Government of India as being de jure independent. Bhutan had in the British period been considered a protectorate outside the international frontier of India. The Government of India entered into a treaty with Bhutan in 1949 continuing this arrangement, and providing that Bhutan would abide by the advice of the Government of India in the conduct of its external affairs.Historically, Sikkim was a British dependency, with a status similar to that of the other princely states, and was therefore considered to be within the frontiers of India in the colonial period. On independence, however, the Chogyal of Sikkim resisted full integration into India. Given the region's strategic importance to India, the Government of India signed first a Standstill Agreement and then in 1950 a full treaty with the Chogyal of Sikkim which in effect made it a protectorate which was no longer part of India. India had responsibility for defence, external affairs and communications, and ultimate responsibility for law and order, but Sikkim was otherwise given full internal autonomy. In the late 1960s and early 1970s, the Chogyal Palden Thondup Namgyal, supported by the minority Bhutia and Lepcha upper classes, attempted to negotiate greater powers, particularly over external affairs, to give Sikkim more of an international personality. These policies were opposed by Kazi Lhendup Dorji and the Sikkim State Congress, who represented the ethnic Nepali middle classes and took a more pro-Indian view.In April 1973, anti-Chogyal agitation broke out and protestors demanded popular elections. The Sikkim police were unable to control the demonstrations, and Dorji asked India to exercise its responsibility for law and order and intervene. India facilitated negotiations between the Chogyal and Dorji, and produced an agreement, which envisaged the reduction of the Chogyal to the role of a constitutional monarch and the holding of elections based on a new ethnic power-sharing formula. The Chogyal's opponents won an overwhelming victory, and a new Constitution was drafted providing for Sikkim to be associated with the Republic of India. On 10 April 1975, the Sikkim Assembly passed a resolution calling for the state to be fully integrated into India. This resolution was endorsed by 97 percent of the vote in a referendum held on 14 April 1975, following which the Indian Parliament amended the constitution to admit Sikkim into India as its 22nd state. 
Question: What was the full name of those who represented the  ethnic Nepali middle classes?
Output (English): the Sikkim State Congress.