By operating a boat in Virginia, you have consented to what kind of test if directed by a marine patrol officer?

When operating a boat in Virginia, you implicitly consent to a sobriety test if directed by a marine patrol officer. This is in line with the implied consent laws that exist in many states, which state that by engaging in certain activities, such as driving or boating, you agree to comply with tests that help ensure safety and legality on the water.

A sobriety test is conducted to determine whether an operator is impaired and is a critical measure to promote safety on the water. The presence of alcohol or drugs can severely impair judgment, coordination, and reaction times, which are crucial for safe boating. Therefore, being subject to a sobriety test underlines the importance of maintaining a safe environment for all boaters and passengers.

In contrast, the other options do not reflect the consent given through boat operation. A blood alcohol test, while also related to measures of impairment, is not the immediate test conducted at the scene. A boating safety test does not relate to law enforcement's authority in this context, and a written examination is not typically a requirement while operating a boat. Thus, the emphasis on sobriety tests aligns with safety regulations in boating law.