There are three identical spheres with different charges $($QA$=+8$C$,$ QB $=+4$C$,$ QC$=-12$C$)$

QA is briefly touched to QC then QC is briefly touched to QB $,.$ The final charge on Q C is $\_\_\_\_\_.$

$($A$)+1$C $($B$)-1$C $($C$)+1/2$ C $($D$)-1/2$ C $($E$)0$ C