Analyze the following code.

```
class Test {
public static void main(String[] args) {
String s;
System.out.println("s is " + s);
}
}
```
a. The program has a compile error because s is not initialized, but it is referenced in the println statement.
b. The program has a runtime error because s is not initialized, but it is referenced in the println statement.
c. The program has a runtime error because s is null in the println statement.
d. The program compiles and runs fine.

a. The program has a compile error because s is not initialized, but it is referenced in the println statement.