The correct answer is A. By Blood.
Doping is the use of performance-enhancing drugs or methods in sports. It is prohibited by most sports organizations, as it gives athletes an unfair advantage. Doping tests are conducted to detect the use of banned substances.
Blood tests are the most common type of doping test. They are used to detect the presence of a wide range of banned substances, including steroids, stimulants, and blood-boosting agents. Urine tests are also used, but they are not as sensitive as blood tests. They are typically used to detect the presence of recreational drugs, such as marijuana and cocaine.
MRI scans are not used to detect doping. They are a type of medical imaging that uses radio waves to create detailed images of the inside of the body. MRI scans can be used to detect injuries, but they cannot be used to detect the presence of banned substances.
In conclusion, the correct answer is A. By Blood. Blood tests are the most common type of doping test. They are used to detect the presence of a wide range of banned substances, including steroids, stimulants, and blood-boosting agents.