One of (4) ________ biggest challenges for teachers is that their role in school management has also changed.Đoạn văn4/40Read the following passage and mark the letter A, B, C, or D to indicate the correct option that completes each of the blanks. One of (4) ________ biggest challenges for teachers is that their role in school management has also changed.Ø (zero article)theanaGiải thíchB. the