This is a Main Idea question.
The author is concerned with explaining a new theory of abiogenic theory, how advocates responded to opponents, instance of pursuing abiogenic theory by Swedish government.
Now, let's go to the answer choices.
A) Whether abiogenic theory is derived from conventional theory or not is not discussed. But considering it's a new and "opposing" theory, it's probably not derived from conventional theory.
B) We are only given one instance of drilling company that puts abiogenic theory into action, it is false to mention "small number of drilling companies" as representing the level of acceptance in the scientific community. (fixed)
C) “superior to conventional” is not stated. We just don't know how sound this abiogenic theory is due to lack of available outcome.
D) Uncertainty has been indicated with the absence of results and criticisms. But stating advocates responses to the criticism and Swedish government's execution on this project from the last paragraph presents that this theory is "plausible." (Correct)
E) Although it is true that advocates answered opponents criticism, statement of "gaining broad acceptance for their theory in the scientific community" is too strong, for it is not stated from the passage.