He was unaware of the financial crisis involed, so his choice was quite .
A. rational
B. arbitrary
C. mechanical
D. predictable
网友回答
A. rational
(答案→)B. arbitrary
C. mechanical
D. predictable
解析：考查形容词词义辨析。rational理性的，合理的；arbitrary武断的，任意的符合句意；mechanical机械的；predictable可预见的。