Find the Given Indefinite Integral $\int x e^{x / 3} d x$

Multiple Choice

Find the given indefinite integral. State whether integration by substitution or integration by parts was used.
- $\int x e^{x / 3} d x$

A) $3 x \mathrm{e}^{\mathrm{x} / 3}-{ }^ 6 \mathrm{e}^{\mathrm{x} / 3}+ C$ ; parts
B) $3 \mathrm{xe}^{\mathrm{x} / 3}-{ }^ 9 \mathrm{e}^{\mathrm{x} / 3}+ C$ ; parts
C) $0.33333333 x \mathrm{e}^{\mathrm{x} / 3}-9 \mathrm{e}^{\mathrm{x} / 3}+ C$ ; substitution
D) $0.33333333 \mathrm{xe}^{\mathrm{x} / 3}-{ }^{} 6 \mathrm{e}^{\mathrm{x} / 3}+C$ ; substitution