Read the passage from an argumentative essay.

(1) It's no wonder students' grades drop when they enter high school. (2) They are suffering various effects of sleep deprivation. (3) They cannot focus, they fall asleep in class, and they often forget what they have read or heard. (4) They may even hallucinate.

How should sentence 3 be revised to clarify relationships among ideas?
by connecting it to sentence 2 with "so"
by connecting it to sentence 4 with "and"
by adding "In addition" to the beginning of the sentence
by adding "Specifically" to the beginning of the sentence