6.
The answer is: C
Explanation
International Mother Language Day is an annual observance that is celebrated worldwide on 21st February. The day aims to promote linguistic and cultural diversity and raise awareness about the importance of preserving and protecting mother languages. The observance also aims to promote multilingualism and encourage people to use their mother language in addition to learning and using other languages. The day was first announced by the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 1999 to commemorate the 1952 Bengali Language Movement in Bangladesh, where students protested for the recognition of their mother language, Bengali, as one of the national languages of East Pakistan. The day is an opportunity to celebrate and promote the diversity of languages and cultures around the world.