Which of the following correctly cites a quotation from an outside source?

"Eating a diet rich in vegetables can lower your risk of chronic diseases" (Source about veggies)
A random doctor says that "eating a diet rich in vegetables can lower your risk of chronic diseases."
According to Dr. Thomas, "Eating a diet rich in vegetables can lower your risk of chronic diseases" (21).
Dr. Thomas (24) says, "eating a diet rich in vegetables can lower your risk of chronic diseases."

According to Dr. Thomas, "Eating a diet rich in vegetables can lower your risk of chronic diseases" (21).