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