I would say it is plausible without knowing the options.
Answer:
b. It adds credibility to the argument they wish to prove.
Explanation:
References from other sources adds credibility to a writers argument, especially when it comes from an expert source. References give an agrument more evidence and support and shows that they are people who agree with said agrument.
All of the other choices show a negative, or false effect of including a reference. Thus, the best option is b.
hope this helps!
The ladybug would be your answer buddy.
