I believe it is c.
I know that d is wrong for sure so my answer would be c
Can we see the paragraph?
The correct answer would be the second choice, "<span>Most of the birds could already fly well (Birds 186).". This is because when using in-text citation, you must include the line being cited and the source in (). you must remember that the source is the Title of the work and the paragraph or page number the line is found. Also a common mistake is made when placing the period. always place the period outside the ().</span>