Solution:
we are given with a graph and we have been asked to find Which of the given options best describes the graph ?
As we know from the vertical line test of a function that a curve reprsents a function , if we draw a vertical line and that line intersect that curve only once.
If that vertical line interscet the given curve more than once it mean that curve does not represent a function.
Here for the given curve if we will draw any vertical line, that line will intersect it more than once.
Hence the given curve does not represent a fimction.
Hence the correct option is D.