A. ∫((x + 1) / (x^2 + x)) dx = ln| x^2 + x |

B. ∫((x + 1) / (x^3 + x)) dx = ln| x + 1 |

C. ∫((x + 1) / (x^3 + x)) dx = ln| x |

D. ∫((x + 1) / (x^3 + x)) dx = ln| x^2 |