At a rough estimate ( 估计), this country is ___________ Great Britain.

A．three times as the size of

B．three times large than

C．three times as larger as

D．three times the size of

有以下程序　　fun(int a, int b)　　{ if(a>b) return(a);　　　else return(b);　　}　　main(　)　　{ int x=3, y=8, z=6, r;　　　r=fun(fun(x,y), 2*z);　　　printf("%d\n", r);　　}　　程序运行后的输出结果是（ ）。

A．3

B．6

C．8

D．12