In the following article, regarding redundant systems, Byron Bailey said
"the 777 has 80 computers and three sets of nearly every system on board – including three radios, three radar transponders, three autopilots and three flight management computers – to ensure a "practically fail safe" operation.
A failure of one will result in transfer, usually automatically, to another. "
Here is what I am asking 777 pilots: Is it correct that there are three transponders?
Flight MH370: former Boeing 777 pilot points to sabotage | Flight MH370 News | The Week UK