Correct option is D
The depth of fusion refers to the distance that the fusion zone extends into the base metal or into the previously deposited weld metal. This is an important parameter in welding, as it indicates how deeply the weld metal has fused with the base material or previous weld pass, ensuring the strength and integrity of the weld.
Cold lap refers to a defect where the weld metal does not properly fuse with the base metal or previous weld layer.
Deposition thickness relates to the thickness of the weld material added.
Dilution refers to the mixing of base metal with the filler metal during welding.
Thus, the correct term for the distance that fusion extends into the base metal or previous pass is the depth of fusion.
