Rachel likes to read books. She records the number of books she read over a period of 5 weeks. The set of ordered pairs below gives the details, where the x-coordinate is the number of weeks since she starts recording and the y-coordinate is the number of books she read each week.
Which of the following describes the set of ordered pairs?
A. both a relation and a function
B. a function only
C. neither a function nor a relation
D. a relation only
