base = 4x2x + 6A4x2+12xB4x2+6xC2x2+6xD8x2+24x Step-by-Step SolutionArea =21×4x×(2x+6)=2x(2x+6)=4x2+12x. Forgetting the ½ gives 8x2+24x.Answer: A) 4x2+12x