Which of the following best describes physical dependence on alcohol?

Physical dependence on alcohol is characterized by the body's adaptation to the presence of alcohol, leading to a situation where the individual feels the need to consume alcohol to function normally. This dependence often results in withdrawal symptoms if alcohol consumption is suddenly reduced or stopped. Individuals who are physically dependent may believe they need alcohol to alleviate these symptoms or to avoid feeling ill, which reinforces their drinking behavior.

The other options highlight different aspects of alcohol behavior but do not effectively capture the essence of physical dependence. Social pressure refers more to external influences that lead an individual to drink rather than a physiological need. Choosing to drink in specific situations may indicate a level of control or moderation, which does not imply dependence. Not drinking at all would suggest the absence of dependence, as it indicates that the individual is not reliant on alcohol in any manner. Therefore, the first option accurately encapsulates the essence of physical dependence on alcohol.