Here, option A is the best answer possible. The first paragraph introduces the central idea of the passage: “Welcome to the world of ‘pharming,’ in which simple genetic tweaks turn animals into living pharmaceutical factories.” The passage then discusses the chronological development of “pharming,” and describes ATryn, a useful drug produced after decades of laboratory experiments. Options B and C are incorrect because the passage does not primarily evaluate research or summarize long-term research findings. Choice D is incorrect because “pharming” is not a branch of scientific study.