Bangladesh became an independent nation in:

Correct option is A

The correct answer is option (a) 1971.
Explanation
Bangladesh became an independent nation on December 16, 1971, following a brutal liberation war with Pakistan, known as the Bangladesh Liberation War. The war was triggered by East Pakistan's struggle for autonomy and independence from West Pakistan, with significant cultural, political, and economic disparities between the two regions. The independence movement was led by Sheikh Mujibur Rahman and the Awami League.

The Pakistan Army engaged in violent military operations to suppress the independence movement, leading to widespread atrocities and a humanitarian crisis. The conflict resulted in significant loss of life, with millions of people being killed or displaced. India intervened in the war in December 1971, leading to a decisive military victory for the Bangladesh Liberation Army. This intervention, along with popular support from the Bangladeshi people, led to the creation of the sovereign nation of Bangladesh.

Information Booster
Bangladesh's independence was the result of a war for freedom that began in March 1971 and ended in December 1971.

The war was a culmination of political and ethnic tensions between East Pakistan (now Bangladesh) and West Pakistan (now Pakistan).

Sheikh Mujibur Rahman became the first President and later the Prime Minister of independent Bangladesh.

India's military support played a crucial role in Bangladesh's independence, leading to a decisive victory over Pakistan.

December 16, 1971, is celebrated as Victory Day in Bangladesh, marking the day of liberation.

Additional Knowledge
(a) 1971: This is the correct answer. Bangladesh achieved independence on December 16, 1971, after a nine-month war of independence from Pakistan. The conflict, known as the Bangladesh Liberation War, culminated in the victory of Bangladeshi forces with significant support from India.

(b) 1972: While Bangladesh was officially recognized as an independent nation in 1972, it had already gained independence on December 16, 1971. The year 1972 saw the formal establishment of governance and political systems in the newly independent state.

(c) 1975: This year does not mark Bangladesh's independence. In 1975, Sheikh Mujibur Rahman, the leader of Bangladesh’s independence movement, was assassinated, which led to significant political instability.

(d) 1977: This year is not significant in the context of Bangladesh's independence. By 1977, Bangladesh had already been an independent nation for six years.