2. Which sentence best expresses the main idea of paragraph 4?
A. When he was a student, Clark avoided daydreaming by focusing on
the head in front of him or on his pencil.
B. While teaching, Clark looks at his students' faces to make sure they
aren't confused.
C. Clark is a visual learner and teacher who always uses hand
movements and writes on the board.
D. Since he wants the students' full attention, Clark makes sure that his
students keep their eyes on him.