Statement (A) : The temperature dependence of resistance is usually given as ${\text{R= R}}_0\left(1+\alpha \Delta t\right)$ The resistance of a wire changes from $100\Omega$ to$150\Omega$ when its temperature is increased from $\text{27°C to 227°C}$ This implies that $\alpha =2.5\times {10}^{-3}/°C$

Statement (B) : $\text{R}={\text{R}}_0\left(1+\alpha \Delta t\right)$ is valid only when the change in the temperature $\Delta T$is small and  $\Delta \text{R}=\left(\text{R}-{\text{R}}_0\right)<<R_{0.}$