Malcolm is taking a speed-reading course. He records the number of words per minute that he can read correctly x weeks after he starts taking the course. The following set of ordered pairs represents the recorded details, where the x-coordinate is the number of weeks and the y-coordinate is the number of words per minute. Which of the following describes the set of ordered pairs? A. a function only B. neither a function nor a relation C. a relation only D. both a relation and a function