We aren't very busy in the shop at the moment; in fact we're rather______.

A．abrupt
B．abnormal
C．absurd
D．accidental

A．game theory can be a very useful theoretical tool to the scientific researchers
B．human behavior can sometimes be governed by evolutionarily stable strategies
C．both the economics and science are founded on the rational human choice
D．only those conscious people will adjust their behavior along with the environment