Please help!!!

Simplify.

(3x^2 + 2x + 7x^3) + (10x^2 + 6x + 9)

A) 7x^3 + 13x^2 + 8x + 9

B) 7x^3 + 30x^2 + 12x + 9

C) 13x^3 + 8x + 16x^3

D) 13x^4 + 7x^3 + 8x^2 + 9