Let $\mathrm{f}:[2,7] \rightarrow[0, \infty)$ be a continuous and differentiable function. Then the value of $(f(7)-f(2)) \frac{(f(7))^{2}+(f(2))^{2}+f(2) \cdot(7)}{3}$, is (where $c \in(2,7))$ ).
(A) $3 \mathrm{f}^{2}(\mathrm{c}) \cdot \mathrm{f}^{\prime}(\mathrm{c})$
(B) $4 \mathrm{f}^{(}(\mathrm{c}) \cdot \mathrm{f}^{\prime}(\mathrm{c})$
(C) $5 \mathrm{f}^{2}(\mathrm{c}) \cdot \mathrm{f}^{\prime}(\mathrm{c})$
(D) None of these