Question

Choose the odd one out.
A. Anthracite
B. Bituminous
C. Lignite
D. Magnetite

Answer 1

Hint: Coal is classified into four main types: anthracite, bituminous, subbituminous, and lignite. The types of iron ores which are used are; hematite, magnetite, limonite and siderite.

Complete Answer:
Looking at the above options:
Option a: Anthracite is a small variety of coal that has a submetallic luster. It has the highest carbon content, the limited impurities, and the highest energy of all types of coal and is the highest ranking of coals. Anthracite contains a high amount of 85 to 95 percent carbon. Anthracite is rarely used today because of its limited quantity and very high expense.
Option b: Bituminous coal is a relatively soft coal containing a tar like substance called bitumen. It is of higher quality than lignite. Its formation is usually the result of high pressure being exerted on lignite. 
Option c: Lignite is a soft, brown, combustible, sedimentary rock formed from naturally compressed peat. It is regarded as the lowest rank of coal due to its very low heat content. It has a carbon quantity around 25 to 35 percent.
Option d: Magnetite is a rock mineral and one of the main iron ores, with the chemical formula $Fe_3O_4$. It is ferrimagnetic, gets attracted to a magnet and can be magnetized to become a permanent magnet itself. It is the extensively magnetic of all the naturally-occurring minerals on Earth. 
Hence, the odd one out is ‘D. Magnetite’.

Note:
- Hematite is the highest quality and most important iron ores.
- Brazil is the largest iron ore producing country.
- China is the largest coal producing country.