What was the difference between a Puritan and a Separatist?

A: Puritans were Catholic and Separatist were Protestant
B: Puritans wanted to change the church within, and Separatist wanted to leave the church.
C: Separatist were Catholic and Puritans were Protestant.
D: Separatist wanted to change the church within, and Puritans wanted to leave the church.