Final answer:
Neither Activity 1 nor Activity 2 is efficient, so the correct answer is d) Neither activity is efficient.
Step-by-step explanation:
Activity 1 is considered efficient when its cost is lower than the cost of the most efficient competitor for the same activity. Since the retesting cost for Lemmons Inc. is $556,000 and the cost for the competitor is $225,000, Activity 1 is not efficient.
Activity 2 is considered efficient when its cost is lower than the benchmarking study for the most efficient level. Since the welding cost for Lemmons Inc. is $1,012,500 and the cost for the most efficient level is $810,000, Activity 2 is not efficient.
Therefore, neither Activity 1 nor Activity 2 is efficient, so the correct answer is d) Neither activity is efficient.