Which of the following welding method uses a pool of molten metal?

Answer: Option B

Submerged arc welding (SAW) uses a pool of molten metal that is formed beneath a blanket of granular flux.

The flux covers the arc and molten pool, preventing contamination from atmospheric gases like oxygen and nitrogen.

This method provides deep penetration, high quality, and efficiency in welding thick materials.

Carbon arc welding, TIG welding, and MIG welding also involve an arc, but they do not use the same submerged molten pool process as SAW.

Hence, the welding method that uses a pool of molten metal is Submerged arc welding.