21 November is observed as –

The correct answer is: B. United Nations Day for South-South Cooperation

21 November is observed as the United Nations Day for South-South Cooperation. It was established by the United Nations General Assembly in 2005 to promote and support South-South cooperation, which is a form of international cooperation between developing countries. South-South cooperation is based on the principles of solidarity, mutual benefit, and equality. It aims to promote economic and social development, as well as to address common challenges such as poverty, hunger, and climate change.

The other options are incorrect.

• World Freedom Day is not a recognized international day.
• Labour Day is celebrated on different dates in different countries. In most countries, it is celebrated on the first Monday of May.
• World Hello Day is celebrated on 21 November. It is a day to promote peace and understanding by saying hello to people you meet.