For the first question about the research on violent video games, the best conclusion is:
b. There is no scientific consensus on the effects.
This reflects the current understanding in academic research where various studies yield mixed results, and there isn't a unified agreement on the impact of violent video games on behavior.
For the second question regarding how the author structures the argument in the passage, the most appropriate choice would depend on the context of the passage. However, if the passage discusses differing perspectives on video games with supporting evidence for each viewpoint, the answer would be:
c. Presenting opposing viewpoints with evidence.
This structure indicates that the author is addressing various arguments while backing them up with corresponding evidence, which is common in discussions around contentious issues like the effects of violent video games.