The correct answer is: A. Magnetite.
Magnetite is a naturally occurring magnetic mineral that is used in compasses to help navigators keep on the right path. It is a black, iron-rich mineral that is found in rocks and ores. When magnetite is placed in a magnetic field, it aligns itself with the field and points north. This property has been used for centuries to help navigators find their way around.
Carbon is a non-metallic element that is found in all living things. It is also found in coal, diamonds, and graphite. Carbon is not magnetic.
Coal is a fossil fuel that is formed from the remains of plants that lived millions of years ago. It is not magnetic.
Uranium is a radioactive metal that is found in rocks and ores. It is not magnetic.
Magnetite is the only option that is magnetic and can be used in compasses.