The correct answer is: C. Labour Day
1 May is observed as Labour Day or International Workers’ Day in many countries around the world. It is a day to celebrate the achievements of the labour movement and to promote workers’ rights.
The first Labour Day was celebrated in 1886 in Chicago, Illinois, United States. The day was chosen because it was the anniversary of the Haymarket Affair, a violent clash between workers and police that resulted in the deaths of several people.
Labour Day is now celebrated in over 80 countries around the world. In some countries, it is a public holiday, while in others it is a day for workers to take part in demonstrations and rallies.
A. World day for War Orphans is observed on 6 June.
B. United Nations Day for South-South Cooperation is observed on 12 September.
D. World Suicide Prevention Day is observed on 10 September.