Which of the following best defines a noble metal?

A noble metal is defined by its resistance to chemical reactions and its low tendency to corrode or tarnish. This characteristic makes noble metals, such as gold, silver, and platinum, particularly valuable for various industrial applications, jewelry, and in certain medical devices. Their ability to maintain their luster and integrity over time, even when exposed to harsh environments, distinguishes them from more reactive metals that can easily oxidize or corrode.

The other options describe traits that do not align with the definition of noble metals. A noble metal can be non-magnetic, inexpensive, or easily obtainable; however, these traits do not inherently define a noble metal. The emphasis on resistance to chemical action is crucial, as it encapsulates the essence of what makes a metal "noble."