Meeting my uncle after these years was an unforgettable moment,()I will always treasure.

问题描述:

Meeting my uncle after these years was an unforgettable moment,()I will always treasure.
Meeting my uncle after these years was an unforgettable moment,( ) I will always treasure.
1.that 2.one 3.it 4.what 选哪个?

that 定语从句先行词,表示的是我所珍惜的时刻