A few books are laid out on a desk in a library. Two are hydraulics, three are mathematics, one is design and four are surveying. Arnolfo selects a hydraulics book and Rommel selects a surveying book. Both Arnolfo and Rommel took their selected books on their respected offices. If Jeson then selects a book at random, what is the probability that he selects a hydraulics book?Required to answer. Single choice.