The correct option is 1 only, as the nationalization of the coal sector in India occurred during the 1970s under Prime Minister Indira Gandhi, fundamentally transforming ownership and control over coal resources. The statement regarding the allocation of coal blocks on a lottery basis is inaccurate, as allocations have evolved to include auction and other competitive bidding processes to enhance transparency and efficiency. Additionally, while India has made strides towards coal self-sufficiency, it still regularly imports coal to meet demand, especially for certain grades, thus the statement on complete self-sufficiency is misleading. Understanding the historical context and current policy framework regarding coal in India is essential for analyzing the sector's evolution and challenges, which is a key area of focus in UPSC examinations.