First of all, do NOT translate to French. It serves no purpose and will trip you. Again, in this section, you have to look at the grammar rules and not to much as the “make sense” part after translating.
As far as the translation goes, it is a bit different:
To reproduce the error, you should not use
Les étudiants voient souvent les théoremes complexe de physique et ennuyeux, sans savoir …
but
Les étudiants voient souvent les théoremes complexe de physique et ennuyeux, ils ne savent pas.
A correct sentence in English would be (translated)
Les étudiants voient souvent les théoremes complexe de physique et ennuyeux. Ils ne savent pas … ou
Les étudiants voient souvent les théoremes complexe de physique et ennuyeux car ils ne savent pas
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Again, what is missing in B is punctuation or a conjunction. Hence the run on sentence. Keep on practicing with official tests and this rather easy part of the SAT will become clearer over time. Google search for available tests. They are all over the place but you might have to overlook the Asian characters. 