Critical Position / Decision in Chess (Part II)

Another critical position from a recent game.

I White to play

I think I can explain a bit further why I chose this precise position today. As White,
two main candidate moves come to mind. 1 Ra8 or 1 c6. Which one would you play and why ? Please analyze each alternative as far as you can.

May I suggest that these kind of positions remind me of IM Dvorestky famous approach where he lets his (GM) students analyze in depth from a given point ?