@General T. Winters (29 May, 2015, 1:43 PM UTC):
There's a fork...
But my final answer is C; Super Conductors.
One could argue that C and D are odd, since they are the only technologies for Artillery and Infantry, respectively.
But I think Super Conductors is more odd since it is the only one that does not require ProtoCrystals to unlock, and does not directly contribute to building BioPlasma units...
It's also the only one to directly unlock a building for you.
Edit 1:
It should also be noted Super Conductors isn't on the same row as the other technologies...