Read the poem "City Trees" by Edna St. Vincent Millay.

The trees along this city street,
Save for the traffic and the trains,
Would make a sound as thin and sweet
As trees in country lanes.

And people standing in their shade
Out of a shower, undoubtedly
Would hear such music as is made
Upon a country tree.

Oh, little leaves that are so dumb
Against the shrieking city air,
I watch you when the wind has come,—
I know what sound is there.

What is the central idea of this poem?

City trees cannot compete with the beauty of trees in the country.
People in cities do not realize that their landscape needs trees.
City trees make sounds that cannot be heard above the commotion.
People in cities need to travel to the country to see trees blooming.