Got all right and it took aroun 5-6minutes.
And it's a bit late but if this is helpful to any future students:
In Q 1, A is not right because the sentence (The research thus far is promising but inconclusive; future scientific advances should allow this theory to be tested more rigorously) that people are referring to actually means the whole research and not the research of the drug only.
In Q3, B is wrong beause the question is what would MOST hinder, not what would hinder. The right answer (D) would be the one that hinders the theory most.