Final answer:
Professional Foresters hold reserved practice and title, with legal authority for exclusive professional forestry activities and protected use of their title.
Step-by-step explanation:
The category of registrants that holds reserved practice and title is a) Professional Foresters. Professional Foresters are typically granted the legal authority through legislation to engage in reserved practice, which includes various professional activities exclusive to their credential. Reserved practice often entails the ability to make forest management decisions, conduct forestry assessments, and prepare forest management plans. The title of 'Professional Forester' is also protected, meaning that only those who meet the necessary educational and professional requirements, and are registered with a governing body, can legally use the title.