Read the text carefully and then choose the correct answers

In a study released early on the JAMA web site, researchers from the University of Toronto and hospitals in the area describe the rapid spread of the coronavirus that causes severe acute respiratory syndrome (SARS). Beginning with a single patient at a community hospital who acquired the virus from another family member who had traveled to China, health care workers became infected. Further spread occurred as patients were transferred among hospitals before the source of inflections and the nature of SARS were identified. Laboratory product companies are working on a test that could be used to diagnose SARS quickly. Many - drug companies are ready working on a SARS vaccine. Even if a vaccine is found, it will surely take several years before it is available for wide public distribution.

Which causes SARS?

• A. 
  HIV
• B. 
  coronavirus
• C. 
  tuberculosis
• D. 
  mumps