B) 1990

Nepal became a constitutional monarchy in 1990. Prior to that, it was an absolute monarchy, with the king having complete control over the government. In 1990, widespread protests and pro-democracy movements led to the establishment of a multiparty democracy and the drafting of a new constitution. This new constitution limited the powers of the king and established a parliamentary system, effectively turning Nepal into a constitutional monarchy.

Nepal became a constitutional monarchy in 1990. This was a result of the Jana Andolan movement, also known as the People's Movement, which demanded greater democracy and freedom in Nepal. As a result of this movement, King Birendra agreed to a new constitution that established a multiparty democracy, with the king as a ceremonial head of state. This constitution also established a bicameral parliament and provided for basic human rights and freedoms. However, the monarchy was abolished in 2008 following a decade-long civil war and the establishment of a federal democratic republic in Nepal.

Background:
Nepal, which was a Hindu kingdom for centuries, transitioned into a constitutional monarchy in the early 21st century.

Constitutional Monarchy:
In the year 1990, Nepal officially became a constitutional monarchy after a pro-democracy movement led by the people resulted in the king agreeing to establish a constitutional monarchy. This change limited the powers of the monarch and established a parliamentary system of government.

Features of Constitutional Monarchy:
- Under a constitutional monarchy, the king's powers are limited by a constitution, and the government is run by elected officials.
- The constitution outlines the rights and responsibilities of the monarch, government officials, and citizens.
- Nepal's transition to a constitutional monarchy was a significant step towards democracy and ensuring the protection of citizens' rights.

Impact of Constitutional Monarchy:
The establishment of a constitutional monarchy in Nepal marked a shift towards a more democratic system of governance, giving the citizens a greater voice in the decision-making process. It also helped in promoting political stability and laying the foundation for a more inclusive and participatory political system.
In conclusion, Nepal became a constitutional monarchy in 1990, marking a significant milestone in the country's political history and paving the way for a more democratic and accountable system of government.