I think one possibility you're not considering, and one which applies frequently when mispronunciation is used as a negative signal, is the case of a shibboleth. A mispronunciation becomes a shibboleth when it's frequently discussed, joked about, known in the field. If you fail the shibboleth test, that's evidence that you're not familiar enough with the field to have encountered the test before, and that may legitimately be a negative signal.

E.g. consider the mispronunciation of nuclear as nu-cu-lar, which carries a stigma and is liable to get you mocked. The mispronunciation has become, by itself, a widely known symbol. There are genuine linguistic reasons for this mispronunciation, and many people grow up with it "innocently", so to speak, but then correct themselves as they start studying physics, because they've heard or read about its shibboleth status; even if you're self-taught and get most of your knowledge from books, it's difficult to miss it. Thus if you pronounce nu-cu-lar, I can infer that either you haven't seen its shibboleth status discussed/maintained, which hints that you haven't been much around physics, in verbal or written form; or that you've seen that, but didn't care to update - your c), which happens rather infrequently.

Contrast this with many possible and actual mispronunciations in physics that did not achieve a shibboleth status - in those cases, I think most often people don't care. Is "boson" pronounced with [s] or [z]? The dictionary happily lists both. Names are mangled on a regular based without listeners batting an eye as long as they understand who it is. And so forth. Even if the listener could plausibly infer your a), I haven't found it to be a strong negative signal in many circles.