At which mountain did God appear to Moses in the burning bush?

Answer: Horeb

Moses led the flock to the far side of the wilderness and came to Horeb, the mountain of God, where the bush burned.

“Meanwhile, Moses was shepherding the flock of his father-in-law Jethro, the priest of Midian. He led the flock to the far side of the wilderness and came to Horeb, the mountain of God. There the angel of the LORD appeared to him in a blazing fire from within a bush. Moses saw the bush ablaze with fire, but it was not consumed.”— Exodus 3:1-2 (BSB)