The correct answer is: A. International Nurse Day
International Nurse Day is celebrated on 25 April every year to commemorate the birth anniversary of Florence Nightingale, the founder of modern nursing. The day is observed to raise awareness about the importance of nurses in the healthcare system and to celebrate their contributions to society.
World Malaria Day is celebrated on 25 April every year to raise awareness about malaria and to promote efforts to prevent and control the disease. The day is observed by the World Health Organization (WHO) and other partners around the world.
World Population Day is celebrated on 11 July every year to raise awareness about population issues and to promote sustainable development. The day is observed by the United Nations (UN) and other partners around the world.
World Mosquito Day is celebrated on 20 August every year to raise awareness about mosquitoes and the diseases they transmit. The day is observed by the World Mosquito Program and other partners around the world.