ANSWER
C. The function is negative when x < 0
EXPLANATION
We want to identify the statement that best describes the function graphed.
To do this, we have to study the graph of the function.
The function graphed has both positive and negative values. The positive values of the function are the part of the function that is above the horizontal red line while part of the negative values of the function is the part of the function that is below the horizontal red line.
We notice that the part of the function that is below the horizontal red line occurs when x is less than 0 (the part of the graph to the left of the vertical red line).
Hence, we can conclude that the correct statement that describes the function is:
The function is negative when x < 0. The answer is option C.