What is a characteristic of stainless steel?

Stainless steel is known for its exceptional toughness and hardness, which make it a popular choice in various applications where durability is essential. The toughness of stainless steel refers to its ability to absorb energy without fracturing, enabling it to withstand impact and stress. Its hardness contributes to its resistance to wear and scratching, making it suitable for environments where it is exposed to rough handling or abrasive materials.

The other options suggest characteristics that do not accurately reflect the nature of stainless steel. For example, while it is relatively strong, it is not known to be rust-prone; in fact, one of its primary advantages is its corrosion resistance due to the presence of chromium, which forms a passive oxide layer that protects the surface. Furthermore, stainless steel is generally heavier than many other materials, so it does not align with the lightweight and flexible description. Lastly, while it has many benefits, stainless steel can sometimes be more costly compared to other materials, especially in mass production scenarios, depending on the specific grade and treatment used.