Respuesta :

3x^3 x 4x^2 = 12x^5

3x^3 x 1 = 3x^3

2x^2 x 4x^2 = 8x^4

2x^2 x 1 = 2x^2

1x x 4x^2 = 4x^3

1x x 1 = 1x

12x^5 + 3x^3 + 8x^4 + 2x^2 + 4x^3 + 1x

Simplify

12x^5 + 7x^3 + 8x^4 + 2x^2 + 1x

Thus, answer is B

Hope this helps!