Suppose $\lim _{x \rightarrow \infty}\left(\frac{x^2+1}{x+1}-a x-b\right)=0$. Then $a^3-b^2$ is

• A

  $-1$
• Correct answer
  B

  $0$
• C

  $1$
• D

  not determinable

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