How does the allusion to famous jazz musicians in “A Poem for My Librarian, Mrs. Long” contribute to the poem?

It illustrates the positive impact that past jazz musicians had on the music of today.
It creates a picture of what the jazz musicians looked like and what their songs sounded like.
It gives the reader a clear picture of the things that people enjoy most during childhood.
It provides specific and vivid details that help the reader better understand the time period.