✨ ベストアンサー ✨ zmic 約2年前 1, 2 and 4 are correct. 3) Whose key is this? zmic 約2年前 (If you want to use "own", the correct sentence is "Who owns this key?") この回答にコメントする
(If you want to use "own", the correct sentence is "Who owns this key?")