A rational function is basically a function which can be defined by a rational fraction, which means that A is definitely not correct. I'd say C. x-3^3/x^2 is the correct answer because of all these cubes and squares.
The correct answer is: y=2/x . A rational function is the quotient of two polynomial functions. Notice that (x - 5)/2 can be simplified into a single polynomial function, so it is not a rational function.
