Which of the method calls and field accesses (shown in underlined bold) in UseSample.java and Sample.java are legal in Java?
public class UseSample {
public static void main(String [] args) {
Sample s1 = new Sample(1, 2);
Sample s2 = new Sample(3, 4);
Sample.ourData = Sample.method1(s2) * s2.method3(s1);
s1.myData = this.ourData + counter;
s2.myInfo = s1.method2(s1) * s2.ourData;
Sample.counter += Sample.method4(s1) + 7;
}
}