(a) $\;h(x)\;$ is not differential at $\;x=0\;$\[\](b) $\;h(x)\;$ is differential at $\;x=0\;$ but $\;h^{'}(x)\;$ is not continuous at $\;x=0\;$\[\](c) $\;h(x)\;$ is continuous at $\;x=0\;$ but $\;h^{'}(x)\;$ is not differential at $\;x=0\;$\[\](d) $h^{'}(x)\;$ is differential at $\;x=0\;$