The fourth paragraph of the passage explains why Higgs's idea of the Higgs field was initially rebuffed by the scientific community: "The paper was rejected. Not because it contained a technical error, but because the premise of an invisible something permeating space, interacting with particles to provide their mass, well, it all just seemed like heaps of overwrought speculation." In other words, the scientific community was skeptical of Higgs's idea because it appeared to be mere theoretical speculation, with no empirical evidence to support it.
Choice A is incorrect because the passage makes clear that Higgs's idea addressed a theoretical problem already recognized by scientists, rather than a problem yet to be noticed by them. Choice B is incorrect because the fourth paragraph implies that Higgs's paper was rigorous (free from "technical error"), rather than problematic at the level of its equations. Choice C is incorrect because the passage never indicates that the acceptance of the Higgs field had the effect of rendering other, earlier theories in physics obsolete.