Which statement best describes how to determine whether fx = x4 – x3 is an even function? A Determine whether –x4 – –x3 is equivalent to x4 – x3. B Determine whether –x4 – –x3 is equivalent to x4 + x3. C Determine whether –x4 – –x3 is equivalent to –x4 – x3. D Determine whether –x4 – –x3 is equivalent to –x4 + x3.