【单选题】

Because it takes longer to install and involves some tinkering to get it to work just right, it’s best for more experienced users.But, oh, what joy! ______ a detailed log of every ad it annihilates, ______ it makes a satisfying ’thunk’ when it nabs one.

A．Not only Killer keeps, but also
B．Not only does Killer keep
C．Only Killer keeps, and
D．Only if Killer keeps