Information in the passage supports which one of the following statements regarding the "first alternative" (line 16)...

Emil-Kunkin on February 8 at 03:35AM

The author tells us that several experiments have failed to confirm the theory, but that the definitive experiment has not yet been attempted. While this latter statement was somewhat tongue in cheek, I think it does speak to a broader sense that it's not really possible to disconfirm the theory either. This is a good match for c.

There are no recent experiments mentioned that support the theory.