ANS:C - manufacture of carbon electrode.

Petroleum coke is mainly used in the manufacture of carbon electrodes. Here's an explanation:

• Petroleum Coke: Petroleum coke, or petcoke, is a carbonaceous solid derived from oil refinery coker units or other cracking processes. It is typically used as a fuel and in various industrial applications due to its high carbon content and energy density.
• Manufacture of Carbon Electrodes: One of the primary uses of petroleum coke is in the production of carbon electrodes. These electrodes are used in various industries, including steel production, aluminum smelting, and other metal processing operations. Carbon electrodes are essential for providing electrical conductivity and thermal stability in these processes.
• Other Uses: While petroleum coke has applications in fueling industrial boilers and as a feedstock for certain chemical processes, its most significant industrial use remains in the manufacture of carbon electrodes.