A.

$\displaystyle

sin^2 x=0+x^2-\frac{x^4}{3!}+\frac{(-1)^{2n}}{{(2n+1)!}^2}{x^{4n+2}}+O(4n+2)

$

B.

$\displaystyle

xe^x=x+x^2+\frac{x^3}{2!}+\frac{x^4}{3!}++\frac{x^ {n+1}}{n!}+O(n+1)

$

C.

$\displaystyle

xsin^3 x=0+x^4-\frac{x^6}{3!}+\frac{(-1)^{2n}}{{(2n+1)!}^2}{x^{5n+6}}+O(5n+4)

$