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Kris was asked to determine whether $f(x)=x^{3}-x$ is even, odd, or neither. Here is his work:$\newline$Step $1$: Find expression for $f(-x)$$\newline$$$\begin{aligned} f(-x) & =(-x)^{3}-(-x) \\ & =(-1)^{3} \cdot x^{3}+x \\ & =-x^{3}+x \end{aligned}$$$\newline$Step $2$: Check if $f(-x)$ is equal to $f(x)$ or $-f(x)$$\newline$$-x^{3}+x$ is the same as$\newline$$$-f(x)=-x^{3}+x \text {. }$$$\newline$Step $3$: Conclusion$\newline$$f(-x)$ is equivalent to $-f(x)$, so $f$ is odd.$\newline$Is Kris' work correct? If not, what is the first step where Kris made a mistake?$\newline$Choose $1$ answer:$\newline$(A) Kris' work is correct.$\newline$(B) Kris' work is incorrect. He first made a mistake in Step $1$.$\newline$(C) Kris' work is incorrect. He first made a mistake in Step $2$.$\newline$(D) Kris' work is incorrect. He first made a mistake in Step $3$.