The fourth revision is correct. it says who was strolling in the sidewalk.
In "Song of Myself", Walt Whitman is writing about individuality and self reliance, as we can see from the first line of the poem: "I CELEBRATE myself, and sing myself", This poem emphasizes the "Self", it can be interpreted as a "cosmic self" it can even be read as an individuality that is collective: "And what I assume you shall assume,
/ For every atom belonging to me as good belongs to you".
Incomplete question. No sentence is provided therefore an answer cannot be provided.
