Final answer:
The depth of preparation for a bevel groove weld is specified in the welding symbols, which would need to be provided to determine the correct depth. Without the specific symbol, the exact preparation depth cannot be discerned.
Step-by-step explanation:
The depth of preparation for a bevel groove weld is typically specified in the tail of the welding symbols provided on a welding drawing. It represents how deep the bevel must be cut into the base material before welding. Without the specific welding symbols mentioned in the question, we cannot determine the exact depth required. Welding symbols follow a standardized system where certain elements of the symbol specify the depth of groove, angle of preparation, and other weld parameters. Therefore, without the exact symbol or additional context, we can't accurately answer whether the depth of preparation is 1/8 inch (option a), 1/4 inch (option b), 3/8 inch (option c), or 1/2 inch (option d).