Peanuts according to Dr Campbell are a healthful substitute to potato chips Which of the following reflects the proper punctuation of the above sentence?

Peanuts, “according to Dr. Campbell,” are a healthful substitute to potato chips.

“Peanuts . . . according to Dr. Campbell . . . are a healthful substitute to potato chips . . .”.
Peanuts: according to Dr. Campbell “[are] a healthful substitute to potato chips”.

“Peanuts,” according to Dr. Campbell, “are a healthful substitute to potato chips.”