Final answer:
The correct revision using commas correctly is choice A, using the comma to separate an introductory clause from the main part of the sentence while keeping the rest of the sentence intact.
Step-by-step explanation:
The revision of the sentence that uses commas correctly is:
A) Looking fearfully over his shoulder, Francis slowly opened the book that he had been expressly forbidden to read by his English teacher.
This sentence correctly places a comma after the introductory clause and does not unnecessarily separate the main components of the sentence. It's important to avoid misplaced commas that can make sentences choppy and obscure the intended meaning. For example, a comma is not needed between a subject and its verb or to separate essential elements that define the subject fully.