[easaman]

Training CAT A1, A2, A3, A4, B1.1, B1.2, B1.3, B1.4, B2, B3

Links for the EASA part 66 licence!

Here is how to get an EASA part 66 CAT-C licence:
An engineer can go from B1 or B2 to C by experience. Or, via an approved university course. Experience in a civil aircraft maintenance environment would also be required.
Here is a UK-CAA detailed CAT-C information!

Category C applicants must either meet B1 or B2 knowledge level as per EC 2042/2003 appendix I .
Experience required is 3 or 5 years as a B1 or B2, depending on your personal background.