(B) Lala Lajpat Rai

"Unhappy India" was written by Lala Lajpat Rai, a prominent Indian author and politician who played a significant role in the Indian independence movement. The book was published in 1928 and addressed various issues and challenges facing India during that time, expressing concerns about the impact of British colonial rule.

1. The Constituent Assembly passed the Constitution of India on November 26, 1949, but it came into force on January 26, 1950. India came into existence as a Republic on January 26, 1950.

2. The Constituent Assembly was established on December 9, 1946, to frame the Constitution of India. There were a total of 389 members in the Constituent Assembly, out of which 299 members were from the Indian National Congress. The Constituent Assembly drafted the Constitution in 2 years, 11 months and 18 days.

3. The Constitution of India is a written constitution. It is the longest-written constitution in the world. It consists of 395 articles, 8 schedules and 12 schedules. The Constitution sets out the structure, powers and functions of the Government of India. It also ensures the rights and freedoms of the citizens.

The Human Development Report (HDR) is released by the United Nations Development Programme (UNDP). The report is an annual publication that measures and analyzes various aspects of human development, including factors such as life expectancy, education, and income. It aims to provide a comprehensive overview of the state of human development globally and to stimulate dialogue and policy changes to improve human well-being.

Hiroshima Day is an annual observance held on August 6 to commemorate the atomic bombing of Hiroshima by the United States in 1945. The bombing killed over 140,000 people and left hundreds of thousands more injured.

Answer: B) Magnetic north Explanation: Wherever on earth we hold a compass, the needle points towards the magnetic North Pole. A compass is a great tool for navigation. Compass is widely used in aircrafts, ships, military services,...