Final answer:
The root problem with Jay Gatsby in "The Great Gatsby" is that he is obsessed with material wealth.
Step-by-step explanation:
The root problem with Jay Gatsby in "The Great Gatsby" is A) He is obsessed with material wealth. Gatsby's obsession with wealth is evident throughout the novel as he throws extravagant parties and spends money lavishly in an attempt to win Daisy's love. His pursuit of material wealth ultimately leads to his downfall.