Reconstruct with shares C

Hi guys, when I use tKey Core Kit, I found that we need to use triggerLogin() then initialize() to get metadata. This means that we must have share A (social login). But in the case I lost the email, and I have only 2 shares C, e.g. one share from Security Question and one share from Passphrase sent to email, which functions can I use to reconstructor the private key?