This is a Must Be True, so we just need to find the textual support for one of the answer choices. Answer choice (B) is supported by lines 44-46: “In his later years, Porter wrote additional chapters for later editions of his book, constantly revising and correcting his findings …” So, Porter made revisions and corrections to the 1943 edition of his book “in later years.” The “trick” in this answer choice is that this reference isn’t near the line “At the time of its first printing in 1943 …” (Lines 26-27). Many test-takers will look at only that part of the passage, and miss the support for (B).
