It 's a tiring day . I slept really late ( or early ) this morning and I could barely think right before I speak . I ' m always having this half a second lag when I talk .
What may be the reason for this situation ?
Pick the best answer from the following options:
A. They had done a lot of walking around that day .
B. They had stayed up late the night before .
C. They needed to drink coffee in the morning .
D. They had school all day .


B