Final answer:
The question concerns the characteristics of welding joints. The correct answer is that lap joints require 100% fusion, not necessarily 100% penetration, which is option B.
Step-by-step explanation:
The question is about the characteristics required in certain types of welding joints, specifically a lap joint. In the context of welding, penetration refers to the depth a weld enters into the base material, while fusion is the process by which the weld metal and the base material melt and mix together to form a joint.
The correct answer to the question is: Some joints, such as the lap joint, may never need 100% penetration, however, they do need 100% fusion. Therefore, the answer is (B) Fusion, Penetration.