Explanation:

First option is correct.

The World Mosquito Day is observed every year on August 20 to raise awareness about the causes of malaria. The observance of the day seeks to created awareness to prevent and also to fundraise for research into the cure of malaria. World Mosquito Day also marks ground breaking discovery of British doctor, Sir Ronald Ross when he had identified link between mosquitoes and malaria way back in in 1897. He had found that female Anopheles mosquitoes transmit malaria between humans.