Register Variable Program

What will be output of following program?

#include<stdio.h>
#include<string.h>
int main(){
int register a;
scanf("%d",&a);
printf("%d",a);
return 0;
}
//if a=25

(A) 25

(B) Address

(C) 0

(D) Compilation error

(E) None of above


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Explanation:
Turbo C++ 3.0: Compilation error

Turbo C ++4.5: Compilation error

Linux GCC: Compilation error

Visual C++: Compilation error



Register data type stores in CPU. So it has not any memory address. Hence we cannot write &a.