Answer:
The revision of the sentence in which commas are used correctly is:
B. Mr. Rodriguez is one of the most popular teachers at my school, but he soon will move to Phoenix, Arizona.
Step-by-step explanation:
The first thing we must keep in mind is that a comma should never separate a subject from its predicate, unless there is an appositive between them. The sentence we are analyzing here has no appositives, which allows us to eliminate letter A for, in it, the comma is placed between the subject and its predicate.
When we have two independent clauses joined by a coordinating conjunction, we should place a comma right before the conjunction. In this case, the coordinating conjunction is "but". That makes letter B the correct option. Letter C is incorrect because it uses another comma immediately after the conjunction. Finally, letter D is also incorrect because it uses no commas at all.