There are two routes to a CAT C:-
ACADEMIC ROUTE:
IMO virtually useless except for those very large companies that may elect to place specifically trained managers in place of seasoned and experienced technicians and engineers.
Academic CAT Cs qualify through completion of selected engineering Degree education and minimal hands on experience with at least one relevant type rating.
VOCATIONAL ROUTE:
The 'normal' qualification through hard work and experience of B1/B2 technicians (though it is normally B1s) over a period of years of providing certified and proven assurance of airworthy aircraft.
Using this route 'normally' would ensure the best performance of a CAT C assurance of an airworthy aircraft.