Final answer:
The U.S.'s hesitance to fully implement the metric system, despite its official adoption, is a case of consumer and economic resistance due to the high costs and cultural familiarity associated with the U.S. customary system. Therefore, the correct option is C.
Step-by-step explanation:
The reluctance of the U.S. to adopt the metric system is an example of consumer and economic resistance. This resistance is largely due to the cost and effort that would be required to transition existing infrastructure and the long-standing cultural familiarity with the U.S. customary system. Many industries would be affected, requiring extensive retooling, education, and updates to comply with metric measurements. Despite the legal adoption of the metric system in the United States, it is not commonly used in everyday practice as it is in countries like the ones shown in green on the provided maps. The major difference between the metric system and the U.S. customary system is that metric units operate on powers of 10, making conversions far simpler, while the U.S. system uses unrelated conversion factors for each unit change.