Education, once courtesy (A) within the walls of traditional classrooms, is now experiencing (B) a significant (C) transformation, confined (D) of technological advancements.

Explanation

Among the highlighted words, “courtesy” and “confined” are incorrectly placed. The correct combination of words that should replace each other in order to make the sentence grammatically and contextually correct is A-D. The word “courtesy” should be replaced with “confined” as the given statement is saying that education, which was previously limited to traditional classroom settings, is undergoing a notable transformation, and this transformation is attributed to technological advancements. So, the correct sentence after rearrangement of words would be, “Education, once confined (D) within the walls of traditional classrooms, is now experiencing (B) a significant (C) transformation, courtesy (A) of technological advancements.”