Which methods are classified as scientific methods of chemical testing?

The correct choice identifies a comprehensive range of scientific methods used in chemical testing. This includes breath analysis, saliva tests, urinalysis, blood analysis, and hair analysis, which all have established methodologies supported by scientific principles to detect and quantify substances.

Breath analysis, for instance, is commonly used for measuring alcohol levels, employing techniques like gas chromatography to provide accurate results. Saliva tests are increasingly utilized due to their non-invasive nature and the ability to detect drugs quickly. Urinalysis is a widely accepted method in both medical and forensic settings for detecting drugs and other substances over a longer period. Blood analysis offers one of the most direct means of testing for various substances in the body, providing precise data on blood concentration levels. Hair analysis is distinct in its ability to provide a history of substance use over time, depending on hair growth rates.

Utilizing this assortment of methods provides a more thorough understanding of an individual's substance use patterns and health status, making option C the most accurate representation of scientific chemical testing methods.