How do base metal thickness and joint design influence heat input and the number of passes required in GTAW?

How do base metal thickness and joint design influence heat input and the number of passes required in GTAW?

• A. Thicker metal requires lower heat input.
• B. Thicker metal and looser joints require fewer passes.
• C. Thinner metals and tighter joints require lower heat input and fewer passes; thicker sections may require higher heat input and multiple passes.
• D. Joint design has no effect.

Answer: (C)