Answer:
- The question asks who can be a mentor in a 'peer-to-peer' model. The options are 'Colleague with comparable experience', 'School principal', and 'Parent expert'.
- The 'peer-to-peer' model implies interaction between individuals of similar standing or roles. Therefore, a 'Colleague with comparable experience' best fits this description. A school principal is in a hierarchical position above teachers, and a parent expert, while valuable, may not always be a peer in the professional context of teaching.
Answer: Colleague with comparable experience