Let f(x) = x and g(x) = x2 - 1. Find g . f and determine its domain. Select one: O x - 1; [0, +co) O x - 1; (-00, -1] U [1, +co) O None among the given choices. x2 - 1; (-00, +00) Vx2 - 1; (-00, -1] U [1, +00) O x - 1; (-00, +00) O Vx2 - 1: [0, +co)