Select the best answer for the question.

17. Which of the following statements is true?

A. A good tool material is one that loses some hardness when it cools down from high temperature.
B. A tool that gets very hot and then cools is probably damaged and should be discarded.
C. A tool should be softer when it gets very hot so it doesn't damage the workpiece.
D. A tool should retain enough hardness when it's very hot that it continues to cut.

A tool should retain enough hardness when it's very hot that it continues to cut. As temperature increases, some materials lose their hardness, becoming malleable or weak like rock at high temperatures. However, for tools to effectively cut at high temperatures, they need to maintain their hardness to carry out their function.

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