Why might an author choose to paraphrase a source? a. to provide a citation for an authoritative source b. to share another's ideas while maintaining his own style c. to introduce words that are unique or unusual d. to give credit to the original author of the ideas

Greetings!

Option B would be correct. An author (may/not) paraphrase a source to share another's ideas while maintaining his own style. 

For instance, say you are writing an essay. You may use a phrase that someone "famous" or noteworthy would use, but of course, not call it your own.

The answer would be d, coherence.