Explanation
Correct answer: C.
Choice C is the best answer. The sentence emphasizes the order in which the two lighthouse keepers began their careers, noting that McNeil, who became the keeper at Bridgeport Breakwater Light in 1904, began her career years after Younghans, who became the keeper at Biloxi Light in 1867.
Why the other choices are wrong
Choice A
Choice A is incorrect because it makes a generalization about the effects of McNeil’s and Younghans’s work; it doesn’t emphasize the order in which the two keepers began their careers. In addition, the sentence misrepresents information from the notes; McNeil was the keeper at a lighthouse in Connecticut from 1904 to 1920, not at a lighthouse in Mississippi from 1867 to 1918.
Choice B
Choice B is incorrect. The sentence claims that Younghans and McNeil were crucial to ensuring the safety of watercraft before lighthouses became automated; it doesn’t emphasize the order in which the two keepers began their careers.
Choice D
Choice D is incorrect. The sentence emphasizes when the lighthouse keepers’ respective careers ended; it doesn’t emphasize the order in which the two keepers began their careers.