Choose the correct simplification and demonstration of the closure property given: (3x^3 + 2x^2 − 5x) − (8x^3 − 2x^2).
5x^3 + 2x^2 + 5x; is a polynomial
5x^3 + 2x^2 + 5x; may or may not be a polynomial
−5x^3 + 4x^2 − 5x; is a polynomial
−5x^3 + 4x^2 − 5x; may or may not be a polynomial
