What is realpolitik?
a. the concept that political decisions of foreign engagement have to be based on the best interests of all parties concerned
b. the concept that political decisions have to be made by consensus or new alliances should be sought out
c. the concept that political decision about foreign engagement have to be based on preserving the interests of your country above all
d. the concept that a single country, acting alone, has the most realistic chance of meeting its own needs

Realpolitik refers to C. the concept that political decision about foreign engagement have to be based on preserving the interests of your country above all.

The concept of realpolitik was coined by German politician and writer Ludwig von Rochau in the 19th century. This term, also referred as Pragmatism, states that politics or diplomacy should be based on the given circumstances and particular factors, rather than on ethical or moral premises. It is also based on the idea that countries must pursue their own interests for the sake of possession and application of power.  

what are the choices?

i believe it was the shinto