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For which of the following does:

$$\lim \limits_{h \to 0} \frac{f(x+h)-f(x)}{h}$$

...yield the same result?

I. $f(x)=\tan^{-1} \sqrt{x}$ II. $f(x)=\ln(1+x)$ III. $f(x)=-\cot^{-1} (\sqrt{x})$

I. $f(x)=\tan^{-1} \sqrt{x}$

II. $f(x)=\ln(1+x)$

III. $f(x)=-\cot^{-1} (\sqrt{x})$

I only.

I and II only.

I and III only.

I, II, and III.