If a student arrives for a practical driving lesson smelling strongly of alcohol or visibly impaired by drugs or medication, what is the instructor's legal and ethical duty?

1. Allow the student to drive on quiet backroads to test their reaction time
2. Charge double price and let the student drive on the motorway
3. Refuse to conduct the driving lesson immediately, prevent the student from driving, explain the zero-tolerance legal prohibition, and offer safe alternative transport home
4. Ignore it as long as the student promises to drive carefully