During which test is a subject asked to stand on one leg for a period of time?

The One-Leg Stand test is specifically designed to evaluate a subject's balance and ability to maintain control while performing a simple task under potential impairment conditions. During this test, the individual is instructed to stand on one leg while the other leg is raised approximately six inches off the ground. They are required to count aloud by thousands (e.g., "one thousand one, one thousand two") until told to stop.

This test evaluates the subject's balance, coordination, and motor skills, which can be affected by alcohol consumption. Observations during the test, such as swaying, using arms for balance, or putting the raised foot down, provide indicators of impairment. The clear focus on balance distinguishes the One-Leg Stand test from the other options listed, making it the correct answer in this context.