Question

in 2007, computer scientist luis von ahn was working on converting printed books into a digital format. he found that some words were distorted enough that digital scanners couldnt recognize them, but most humans could easily read them. based on that finding, von ahn invented a simple security test to keep automated \bots\ out of websites. the first version of the recaptcha test asked users to type one known word and one of the many words scanners couldnt recognize. correct answers proved the users were humans and added data to the book - digitizing project. which choice best states the main purpose of the text? a. to discuss von ahns invention of recaptcha b. to explain how digital scanners work c. to call attention to von ahns book - digitizing project d. to indicate how popular recaptcha is

Explanation:

The text starts with von Ahn's work on book - digitizing, then focuses on his invention of reCAPTCHA due to scanner limitations. It details the first version of reCAPTCHA and its dual purpose. The main focus is on the invention of reCAPTCHA.

Answer:

A. To discuss von Ahn's invention of reCAPTCHA