attribute sth to sth/sb

865/ The head of the marketing department attributed success in the overseas market to _______ motivated and hard-working employees.
a. them
b. they
c. itself
d. its

<Economy TOEIC _ Volume 1>

★ attribute sth to sth/sb: quy cái gì cho cái gì/ ai
* Phía sau khoảng trống đã có cụm danh từ -> cần 1 tính từ sở hữu
=> D is correct