OG详解-OG8 阅读 Q24

Choice A is the best answer because it most accurately states the main purpose of the text. After providing a brief introduction to computer scientist Luis von Ahn, the text focuses on discussing how von Ahn’s digitization work led to the invention of a digital security test known as reCAPTCHA. 
Choice B is incorrect because the text doesn’t address how digital scanners work. Choice C is incorrect. Although the text mentions von Ahn’s book-digitizing project, that information is provided as a detail, not as the main purpose of the text. Choice D is incorrect because the text doesn’t provide any indication of reCAPTCHA’s popularity; instead, it describes reCAPTCHA’s origin.