What are the vertical and horizontal asymptotes for the function fx=x^2+x-6/x^3-1? a. vertical asymptote: x = 1 horizontal asymptote: none b. vertical asymptote: x = 1 horizontal asymptote: y = 0 c. vertical asymptote: x = –2, x = 3 horizontal asymptote: y = 0 d. vertical asymptote: x = –2, x = –3 horizontal asymptote: none