Which sentence contains a comma splice?

a) in order to prove his identity, gatsby shows nick the medal he won in the war.

b) because she's such a flake, daisy cries when she sees gatsby’s collection of shirts.

c) at the end of the novel, nick decides to leave new york because of what has happened.

d) jay gatsby achieved his wealth in order to win over daisy, his wealth was not enough to steal her away from tom.