37. What is the main idea of Paragraph B? (A) West Nile virus is native to North Africa where it infects birds and is carried by mosquitoes. (B) In 1999, doctors in New York City were puz e puzzled when birds died and people got sick. (C) Birds and mosquitoes can sometimes spread diseases from one continent to another. (D) International travelers should get shots before traveling and take malaria medicine.