37給定以下的 C 語言函式宣告： double fn1(void); int fn2(int n,double x); double fn3(double,int,double,int) ; double fn4(int a,int b,int c,int d); 則下列各函式呼叫敘述中，何者在編譯時會發生錯誤？
(A)int a; a = fn1();
(B)int a = 0, b = 0; b = fn2(a,b);
(C)double r = 0.0; int a = 0; a = fn3(r,a,r,a) ;
(D)int a = 0, b = 0, c = 0, d = 0, e = 0; a = fn4(a,b,c,d,e);