Let f(x) and g(x) be polynomials as shown below. Which of the following is true about f(x) and g(x)? A. f(x) and g(x) are not closed under subtraction because when subtracted, the result will be a polynomial. B. f(x) and g(x) are closed under subtraction because when subtracted, the result will be a polynomial. C. f(x) and g(x) are not closed under subtraction because when subtracted, the result will not be a polynomial. D. f(x) and g(x) are closed under subtraction because when subtracted, the result will not be a polynomial.