Is it acceptable to copy$-$and$-$paste a sentence written by someone else into your paper and then just add quotation marks around it$?$

Question $8$ options:

a$)$

Yes, it was only a sentence not a full paragraph.

b$)$

No$,$ this requires a citation or footnote $($check the required referencing style for your unit$)$ and a full reference in your reference list.

c$)$

Yes, that shows it is not original text.