WHAT DOES THE WORD ‘THEY’ IN LINE 3 REFER TO

39. - CAC BAI KIEM TRA TIENG ANH 8 THEO UNIT
CAC BAI KIEM TRA TIENG ANH 8 THEO UNIT

39. What does the word ‘they’ in line 3 refer to?

A. sounds B. the Bells C. the American D. the deaf.