$\int \frac{x+1}{x^3-1} d x=$

• A

  $\frac{1}{3} \log \left(\frac{x+1}{x^2+x+1}\right)+c$
• Correct answer
  B

  $\frac{1}{3} \log \left(\frac{(x-1)^2}{x^2+x+1}\right)+c$
• C

  $\frac{1}{3} \log \left(\frac{x-1}{x^2+x+1}\right)+c$
• D

  $\frac{1}{3} \log \left(\frac{(x+1)^2}{x^2-x+1}\right)+c$

Hence, the correct answer is option: 'B'.