Question

Which group of lines in this excerpt from John Keats’s “Ode to Autumn” illustrates the "music" of autumn?

Answer 1

I would say this group of lines illustrates the music of autumn, because the word choir is mentioned:
"Then in a wailful choir the small gnats mourn 
 Among the river sallows, borne aloft 
Or sinking as the light wind lives or dies".

Answer 2

Answer:

Then in a wailful choir the small gnats mourn  

Among the river sallows, borne aloft

Or sinking as the light wind lives or dies;

Explanation: