Impairment from alcohol begins with the very first drink. This means that even one drink can start to affect your physical and mental capacities in subtle ways. It's a common misconception that impairment only starts to occur at a certain blood alcohol concentration (BAC) level, such as 0.08. However, scientific studies and expert opinions confirm that any amount of alcohol can begin to impair your judgment, coordination, and reaction times, which are critical for activities such as driving.
Therefore, the correct answer is:
C. With your first drink.