Switched Capacitor Basics
None of those circuits are actually switched capacitor although these might help in explaining some concepts. 

Although it has only capacitors in the signal path, 12a is an amplifier whose frequency response goes all the way down to DC. It does have a basic problem, however: the amplifier bias is not well-defined without additional circuitry. The DC offset from input to output is otherwise arbitrary. 

12b is the simplest possible biasing alternative for this circuit. The problem is that it introduces a zero at DC and a pole proportional to 1/R, that  translates into a first- order highpass response. Which means that it blocks DC, only frequencies above the pole will see the same amplification as in 12a.