What is the correct pronunciation of "Ra's Al Ghul"?

Across the four screen/game adaptations I'm familiar with, I've heard the name "Ra's" pronounced as "Raz", "Rah-z" and "Ray-sh" - often times, differing even within the same work.

Is there an official or intended (by creators, editors) pronunciation of the name?

WARNING: massive Arrow spoilers for the most recent episode in the this linked video . (Even the title of the video contains a spoiler).