A looks better since the taller hut against the sky balances out the mountain, composition wise, that hut functions like a second mountain rising up. Also, the huts and tree line and mountain all flow together. Because the background elements are opaque, the tree line and mountain also work together to give the impression of perspective, as though they areflowing off into the distance. The tree line in the B pic balances out the mountain in a more 2D way, but the A pic feels more natural.