Hey Joanna - I also am not an expert but here are my two cents.
The argument proposes a causal relationship. The "cause" is increased religiosity. Note: The cause is not students attending church. It is "religiosity" or a spirit of faith. The "effect" is lower cheating.
You can weaken this conclusion by showing that the cause/effect relationship is not valid or by finding an alternative cause for the lower cheating.
Answer C looks attractive as an alternative cause but the dates don't match up. The change to proctor exams happened fifteen years ago and the reduction in cheating is "recent"
Answer A shows that the cause/effect relationship may not be valid. If the students attend church only for social reasons then they do not have increased religiosity. Therefore, the conclusion falls apart that religiosity is the reason for less cheating.
Hope that helps...
