Board Thread:Game Updates/@comment-26091666-20160624120924/@comment-26574811-20160625022837

OK after a bit of research, this is my guess:

K2A: A(甲) means Armoured (装"甲"), so it is used on armoured carrier remodels.

K2B: B(乙) means B-class destroyers (Akizuki-class), since Kasumi K2B is focused on AA and other fleet escort roles.

K2D: D(丁) means D-class destroyers (Matsu-class), since Asashio K2D would most likely focus on transport and transport escort roles, just like the Matsu-class

So why is C skipped?

Because C means C-class destroyers (Shimakaze), and no DDs have such remodels, except if Amatsukaze is going to receive her K2.