If $\mathrm{f}(\mathrm{x})$ is a differentiable function and $\phi(\mathrm{x})$ is twice differentiable function and $\alpha$ and $\beta$ are roots of the equation $f(x)=0$ and $\phi^{\prime}(x)=0$ respectively, then which of the following statement is true ? $(\alpha<\beta)$
(A) there exists exactly one root of the equation $\phi^{\prime}(x)$. $\mathrm{f}(\mathrm{x})+\phi^{\prime \prime}(\mathrm{x}) \cdot \mathrm{f}(\mathrm{x})=0$ on $(\alpha, \beta)$
(B) there exists atleast one root of the equation $\phi^{\prime}(x)$. $f(x)+\phi^{\prime \prime}(x) \cdot f(x)=0$ on $(\alpha, \beta)$
(C) there exists odd number of roots of the equation $\phi^{\prime}(x)$. $\mathrm{f}(\mathrm{x})+\phi "(\mathrm{x}) \cdot \mathrm{f}(\mathrm{x})=0$ on $(\alpha, \beta)$
(D) None of these