C-virus is not made from the T-Veronica virus cause the t-vernica virus died with alexia ashford which albert wesker failed to get for white umbrella in RE:code vernica X.Nor is it made from the G-virus because the g-virus was never completed ny willam birkin and sceond cannot be made better or perfected because the virus has to change the skeletal and muscular stucture in order to host the extra eye and massive claws.The C-virus is made from Dr.Marcu's hive virus from resident evil 0 to which gives the infected person insectile appendages and features,which is reduced by the t-virus to induce minmail changes to the infected person like:extra eyes,increased strength,and over-lapping vision.