Let f be a function such that f (-1) = 1. At each point (x,y) on the graph of f, the slope is given by 1% = -x2 – xy + y2 – 1. Which of the following statements is true? A s a relative minimum at x = -1. s a relative maximum at x = -1. f has neither a relative minimum nor a relative maximum at x = -1. There is insufficient information to determine whet s a relative minimum, a relative maximum, or neither at x = -1.