2110012504
Level:
B
Choose the graph of a function $f$ that satisfies
\begin{gather*}
f'(1) \text{ does not exist}; \\
f''(x) < 0 \text{ if } x < 1 ; \\
f''(x) < 0 \text{ if } x > 2; \\
f''(x) > 0 \text{ if } 1 < x < 2
\end{gather*}
($f'$ is the derivative of a function $f$, $f''$ is the second derivative of a function $f$).
