The parabola y=−14x2y = -\frac{1}{4}x^2y=−41x2 has its focus at which point?
(−1,0)(-1, 0)(−1,0)
(0,1)(0, 1)(0,1)
(0,−1)(0, -1)(0,−1)
(1,0)(1, 0)(1,0)