If a function $f: \mathbb{Z} \rightarrow \mathbb{Z}$ is defined by $f(x)=x-(-1)^x$, then $f(x)$ is

• A

  one-one, but not onto
• B

  onto, but not one-one
• Correct answer
  C

  both one-one and onto
• D

  neither one-one nor onto

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