He planted a tree on the hill his father who died 3 years ago.A. in memory of B. in order

He planted a tree on the hill his father who died 3 years ago.
A. in memory of B. in order to C. instead of

解析：他在山上种了一棵树以纪念三年前去世的父亲。in memory of：作为对某人的纪念， in order to：为了，目的是，instead of;代替。根据句意可知应选A。

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