Mark the letter A, B, C, or D on your answer...

Câu hỏi: Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.

A. Although the teaching lesson was clear, there was a real challenge to the students.

B. Despite the teacher's clear explanation of the lesson, students had difficulty understanding it. 

C. In spite of explaining the lesson clearly, students themselves found it hard to understand it. 

D. Though explained clearly, tfifc lesson of teaching was difficult to students.