Which tire feature must be checked for adequate depth during vehicle inspections?

Answer: B — 1.6 mm

The correct depth that must be checked for tire tread during vehicle inspections is 1.6 mm. This measurement is crucial because it represents the minimum legal tread depth requirement for safe driving in Alberta. Adequate tire tread ensures that the tires maintain traction on wet or slippery roads, significantly impacting stopping distances and overall vehicle control. When tread depth falls below this threshold, tires may become ineffective in channeling away water, increasing the risk of hydroplaning and reducing the vehicle's grip on the road surface. Thus, ensuring that the tires have at least 1.6 mm of tread depth is essential for the safety of the driver, passengers, and other road users.