[问答题]
The diagram shows part
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1. 1. Write down the value of $f^{\prime}(x)$ at A .
2. Hence, show that A corresponds to a maximum on the graph of f .
2. Which of the points A, B, C, D corresponds to a minimum on the graph of f .
3. Which of the points A, B, C, D corresponds to a point of inflection of f . Justify your answer.