Directions: In the following question, four options are given. You have to choose the best way of writing the sentence in the context of correct English usage. Ensure that the meaning of the sentence remains unchanged.

He had reached his office when he realized that he had left his room' s window open.

He had reached his office when he realized that he had left his room' s window open.

He reached his office when he realized that he had left his room' s window open.

He had reached his office when he realized that he had left the window of his room open.

He had reached his office when he could realize that he had left his room' s window open.