What is the graph of the rational function?
y = [ x^2 - 4x + 3 ] / [ x^2 - 9 ] factor numerator, denominator
y = [ ( x - 1) (x - 3) ] / [ (x + 3) ( x - 3) ] simplify
y = ( x - 1) / ( x + 3)
Since we have same power / same power, this graph will have a horizontal asymptote at y= 1 and a vertical asymptote at x = -3
"D" is the correct answer
Here is the graph : https://www.desmos.com/calculator/ngyzzm8hdr