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 .

Question with options to choose from: Why is the narrator failing to wake up early ?

(a). None of the above choices .
(b). The narrator does not get enough sleep .
(c). The narrator has a medical condition .
(d). The narrator has kids .
(b).