Help ASAP!!

Put the polynomial in standard form

5x-3x^3+1+6x^2

A: -3x^3+6x^2+5x+1
B: 1+6x^2+5x-3x^3
C: 6x^2+5x-3x^3+1
D: -3x^3+5x+6x^2+1