The option that could cause a long-held theory to be challenged or even overturned by the scientific community is:
new evidence that better matches the new theory than previous evidence.
Scientific theories are based on evidence, and when new evidence emerges that better supports an alternative explanation, it can lead to the re-evaluation and potentially the overturning of existing theories. The other options provided are not based on scientific principles and do not represent how scientific theories are typically challenged or revised.