Limit Definition of Derivatives

Which of the following limits represents a derivative?
i) lima0 f(x+a)f(x)xa\displaystyle \lim_{a\to0}\ \frac{f\left(x+a\right)-f\left(x\right)}{x-a}

ii) limx3 x3x3\displaystyle \lim_{x\to3}\ \frac{\sqrt{x-3}}{x-3}

iii) limh0 ln(x+h)ln(h)h\displaystyle \lim_{h\to0}\ \frac{\ln\left(x+h\right)-\ln\left(h\right)}{h}

iv) limx5 ex+1e5x5\displaystyle \lim_{x\to5}\ \frac{e^{x+1}-e^5}{x-5}
More Basics of Derivatives Questions:
More The Limit Definition of a Derivative Questions: