Final answer:
The committee responsible for overseeing the capacity of registrants is the Professional Regulation Committee.
Step-by-step explanation:
The committee responsible for concerning the capacity of the registrant in terms of PT/Client relations, discipline, fitness to practice, and Inquiries/Complaints/Reports is known as the Professional Regulation Committee.
They are responsible for developing and implementing regulatory programs, processing applications for licenses and other filings, encouraging the development of innovative services, and conducting investigations and analyzing complaints. This committee plays a crucial role in ensuring that healthcare professionals adhere to the highest standards of practice.