Before 1986 physicists believed they could describe the universe in terms of four universal forces. Experiments then suggested, however, a fifth universal force of mutual repulsion between particles of matter. This fifth force would explain the occurence in the experiments of a smaller measurement of the gravitational attraction between bodies than the established theory predicted.
Which, if true, most strengthens the argument that there is a fifth universal force?
B) No previously established scientific results are incompatible with the notion of a fifth universal force.
C) Some scientists have suggested that they alleged fifth universal force is an aspect of gravity rather than being fundamental in itself.
Can anyone explain why each answer is right and wrong? Thanks in advance.