Finish parent and current activity in Android

Question

I have 3 activities. Activity A which leads to activity B, which in turn can go back to activity A or start activity C. However, if I press back in activity C the app should

Answer 1

Create instance of ActivityB.

on ActivityB.java

public static ActivityB instanceOfActivityB;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    instanceOfActivityB = this;
}

on ActivityC.java

void onClose() {
   ActivityB.instanceOfActivityB.finish();
   finish();
}

Hope it helps!