Depend on your requirement , if you wants to finish activty B and c
  on Button Click then use Flag FLAG_ACTIVITY_CLEAR_TOP with intent
  flag. in this case on newIntent will be called, you can get bundle
  from it.
@Override
    protected void onNewIntent(Intent intent) {
        // TODO Auto-generated method stub
        super.onNewIntent(intent);
    } 
if you do not wants to close activity B and C then use 
Intent intent = new Intent(this, YourActivity.class);
Bundle bundle = new Bundle();
intent.putextras(bundle);
startActivity(intent);
if any issue then let me know.