Answer:
Sentence A.
Explanation:
When using someone else's thoughts, ideas, sentences etc. in your work, it's necessary to avoid plagiarism, by properly quoting them.
There are basically two essential things to pay attention to:
- when paraphrasing someone one must put internal quotation just after the paraphrased piece of information. Internal quotation consists at least of the author's last name and page number from which the information was taken.
- when quoting someone (using his work word-by-word), the quoted content must be placed between quotation marks, followed by internal quotation.
Of course, regardless of the internal quotation, the proper citation must be provided at the end of the work, in the citation list.
So, with all this in mind, we can see that sentence A failed to obey these rules, which marks it as plagiarism.