The correct answer is: D. Steel
The Bessemer process is a process for making steel by blowing air through molten pig iron to remove impurities. The process was invented by Henry Bessemer in 1856 and was the first commercially successful method for mass-producing steel.
Pig iron is a type of iron that is produced in a blast furnace. It is a hard, brittle material that is not suitable for most purposes.
Cast iron is a type of iron that is produced by melting pig iron and then pouring it into molds. It is a strong, but brittle material that is used to make things like pipes, valves, and castings.
Wrought iron is a type of iron that is produced by hammering and rolling pig iron. It is a soft, ductile material that is used to make things like nails, chains, and tools.
Steel is a type of iron that is produced by adding carbon to pig iron. It is a strong, tough material that is used to make things like cars, buildings, and bridges.