Richard Powers’ The Echo Maker, ____ novel set in ___ small town of Kearney, Nebraska, US, has won the 57^th US National Book Award for fiction.

A．the; the

B．a; a;

C．a; the

D．/; the

一个小数扩大到它的3倍后得到的数比原数大5.4，这个小数是（    ）。