Final answer:
Metals that are soft and can be easily shaped are described as malleable, which means they can be made into thin sheets. Malleability is a key property of metals, different from being brittle, tough, or hard. Therefore, the correct answer to the student's question is D. Malleable.
Step-by-step explanation:
Metals that are very soft and easily worked are said to be malleable. This property allows metals to be pounded into thin sheets without breaking. Being malleable is one of the distinctive characteristics of metals alongside being shiny, ductile (able to be drawn into wires), and having the ability to conduct heat and electricity well.
Unlike malleable materials, brittle substances break easily, tough materials can absorb energy without fracturing, and hard materials resist scratching and indentation. Therefore, the correct answer to the student's question is D. Malleable.