Which of the following is a requirement for a supervising driver?

The requirement for a supervising driver is that they must be at least 21 years old and possess a valid driver's license. This stipulation ensures that the supervising driver has sufficient experience and maturity to guide a learner driver safely. The age and licensing requirements reflect a balance of legal responsibility and driving competence, aimed at ensuring the safety of both the learner and others on the road.

While a supervising driver needs to have experience, simply having a certain number of years of driving (as indicated in the last option) does not specifically address the age and licensing criteria, which are crucial for the supervisory role. Additionally, not all supervising drivers need to be licensed instructors, as many qualified individuals over the age of 21 may fulfill the requirements without being professional driving instructors. This underscores the focus on both age and validated driving capability, making it essential for a supervising driver to meet these specific conditions.