Q. Which of the 3 transistor configuration is best to use in cascade if maximum voltage gain is to be realized?

 The common collector configuration is not used for intermediate stages because the voltage gain of such a stage is less than unity. Hence it is not possible to increase the overall voltage amplification by cascading common collector stages.

 Ground-base RC-coupled stages are seldom cascaded because the voltage gain of such and arrangement is approximately the same as that of the output stage alone. 

In the common emitter stage however the short circuit current gain is greater than unity. It thus makes it possible to increase the voltage amplification by cascading such stages. 

Thus in a cascade the intermediate transistor should be connected in a common emitter configuration.