—Is the tie made ________ silk?

—Yes. It's made ________ Italy.

 [ ]

A. from; in

B. of; in

C. from; of

D. of; from

计算斐波那契数列第n项的函数定义如下：

int fib(int n)

if(n= =0)return 1;

else if(n= =1) return 2;

else return fib(n-1)+fib(n-2);

若执行函数调用表达式fib(2)，函数fib被调用的次数是（）

A.1

B.2

C.3

D.4