As for this problem, the most probable and the most likely to be the answer would be C. design new experiments to test the proposed hypothesis.
This has always been what the scientists and researchers have been doing, proving and disproving hypothesis, theories, and even established facts, but only for those facts that either they have a personal argument of it or of which they believe isn't supposed to be. Though some might reject the hypothesis right away, they couldn't claim it since they would be asked to show their evidences and side of argument. Changing the hypothesis to fir their own findings would be just entirely out of the picture and assuming that the hypothesis is true for all viruses would be not likely to be done by a scientist or a researcher.
