Which best represents the domain and range of the reciprocal of the lienar function y = -3x-9

Question

a) d: {x|x∈R, x ≠ -3} r: {y|y∈R, y ≠ 0}

b) d: {x|x∈R, x ≠ 0} r: {y|y∈R, y ≠ 3}

c) d: {x|x∈R, x ≠ 3} r: {y|y∈R, y ≠ -3}

d) d: {x|x∈R, x ≠ 9} r: {y|y∈R, y ≠ 0}

Answer 1

I get answer [a], because the reciprocal 1/y = - 1/[3(x + 3)] has vertical asymptote at x = -3 and horizontal asymptote at y = 0 (when x approaches infinity).