Which sentence is punctuated correctly?
A: “Understand yourself, and you will understand everything, said Shunryu Suzuki.”
B: “Understand yourself, and you will understand everything,” said Shunryu Suzuki.
C: “Understand yourself, and you will understand everything, said Shunryu Suzuki.
D: Understand yourself, and you will understand everything, said Shunryu Suzuki.