What happens to the validity of a breath test if the subject eats or drinks during the deprivation period?

When a subject consumes food or drinks during the deprivation period, it can significantly impact the validity of the breath test results. The deprivation period is designed to ensure that the individual has not ingested any substances that could influence their breath alcohol concentration. If a person eats or drinks, it can introduce residual alcohol from the mouth or throat into the breath sample, leading to falsely elevated readings. This is because the mouth alcohol can evaporate and be read by the device, which measures the breath alcohol content, rather than accurately reflecting the subject's true blood alcohol concentration. Therefore, allowing food or beverages during the deprivation window can compromise the accuracy and reliability of the test results.

In contrast, the other options do not accurately reflect the consequences of eating or drinking during this critical period. The breath test is designed to be sensitive, and any interference from external substances will indeed lead to inaccurate results.