The answer would be D.
The sentence without punctuation errors is "Vegetables, fruits, and whole grains are healthful but doughnuts, cake, and candy are not." It uses commas and the conjunction 'but' correctly to separate list items and connect clauses.
The sentence that does not contain any punctuation errors is:
D. Vegetables, fruits, and whole grains are healthful but doughnuts, cake, and candy are not.
This sentence correctly uses commas to separate items in a list and the conjunction 'but' to connect two independent clauses. In sentence A, the comma before 'but' is not needed because the conjunction is connecting two clauses, not items in a series. Sentence B incorrectly uses a semicolon before 'but' where a comma is sufficient since the clauses are closely related in thought. Sentence C lacks the necessary conjunction 'but' to properly connect the two independent clauses.
The sentence without punctuation errors is A: "Vegetables, fruits, and whole grains are healthful, but doughnuts, cake, and candy are not." This choice uses correct punctuation to separate two independent clauses. Each other option contains some form of punctuation errors.
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