Answer:
B. The decay of American values
Step-by-step explanation:
The Valley of Ashes in The Great Gatsby is a barren wasteland that is situated between East Egg and West Egg. It is a valley in which ashes and waste of the rich are dumped upon. It is described in Chapter 2 of the story where Tom and Nick approach it on their way to pick up Myrtle Wilson at her husband's garage.