In my opinion, you can use it to define words and find more suitable words (they usually have a thesaurus built into the definition), and find words that seem more elegant or mature.
The answer should be c. you should have multiple sources but not just any. they should still be on topic with what the research is about and credible on top of that.
Sentences with errors in parallel structure have conflicting tense and structure. The correct answer is C.
