In line 15, to which of the following does the word "They" refer? A. Lighthouses B. Differences C. Quarters D. Features

A

Dựa vào câu phía trước và câu chứa đại từ “they” “Not withstanding differences in appearance and construction, most American lighthouses shared several features: a light, living quarters, and sometimes a bell (or, later, a foghorn). They also had something else in common...” ®đại từ này đề cập đến đối tượng “lighthouses”