OG详解-OG4 文法 Q12

Choice A is the best answer. “Therefore” logically signals that the action described in this sentence—the researchers theorizing that the dish was named for its effect on diners—is a result or consequence of the previous observation that the dish had a calming effect.
Choice B is incorrect because “alternately” illogically signals that the action described in this sentence offers an alternative or contrast to the previous observation that the dish had a calming effect. Instead, the action is a result or consequence of that observation. Choice C is incorrect because “nevertheless” illogically signals that the action described in this sentence occurs despite the previous observation that the dish had a calming effect. Instead, the action is a result or consequence of that observation. Choice D is incorrect because “likewise” illogically signals that this sentence merely adds a second, similar detail to the previous observation that the dish had a calming effect. Instead, this sentence describes an action that is a result or consequence of that observation.