Simplify the following expression.
3x +2x³-5x² + 4x² +6x-2x-3x +7x -3x³
A. 10x¹ + x² + x² + 4x
B. 7x -6x +5x²³ - x² + 4x
C. 7x5x3x² + 4x
D. 7x +6x*- x² - x² + 4x
