If f$($A$,$B$,$C$)=$ summation $1,2,3,4,5,6,7$ then the compliment ofFf isA$+$B$+$Cb$.$A$\text{'}+$B$\text{'}+$C$\text{'}$c$.$A'B'C'd$\mathrm{.}0$e$.$None of thesef$\mathrm{.}1$