Given: What is the result?

Given the code fragment:
class Student {
int rollnumber;
String name;
List cources = new ArrayList();
// insert code here
public String toString() {
return rollnumber + " : " + name + " : " + cources;
}
}
And,
public class Test {
public static void main(String[] args) {
List cs = newArrayList();
cs.add("Java");
cs.add("C");
Student s = new Student(123,"Fred", cs);
System.out.println(s);
}
}
Which code fragment, when inserted at line // insert code here, enables class Test to print
123 : Fred : [Java, C]?

Given the content of three files:

Which statement is true?

Given:

What is the result?

Given:

What is the result?