# $|x| <1$, the coefficient of $x^3$ in the expansion of $\log (1+x+x^2)$ in ascending powers of $x$, is :
( A ) $\frac{2}{3}$
( B ) $\frac{4}{3}$
( C ) $-\frac{2}{3}$
( D ) $-\frac{4}{3}$