Which of the Following Sequences Correctly Arranges the Three Major $\rightarrow$

Which of the following sequences correctly arranges the three major sleep disorders described in your text from most to least common?

A) insomnia $\rightarrow$ narcolepsy $\rightarrow$ sleep apnea
B) sleep apnea $\rightarrow$ insomnia $\rightarrow$ narcolepsy
C) narcolepsy $\rightarrow$ insomnia $\rightarrow$ sleep apnea
D) insomnia $\rightarrow$ sleep apnea $\rightarrow$ narcolepsy