SignOut is not working in Fragment using Item Menu with firebase

This is my Profile fragment and I am having three of them in main Activity. Here I am using Sign out functionality but it is not working.

package com.example.user.transroads;

import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.AlertDialog;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;

import com.google.firebase.auth.FirebaseAuth;


public class ProfileFragment extends Fragment {

private FirebaseAuth firebaseAuth;

public static ProfileFragment newInstance() {
    ProfileFragment fragment = new ProfileFragment();
    return fragment;
    // Required empty public constructor
}


@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    firebaseAuth = FirebaseAuth.getInstance();
    setHasOptionsMenu(true);
}

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    // TODO Add your menu entries here
    super.onCreateOptionsMenu(menu, inflater);
    inflater.inflate(R.menu.item_menu, menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()){
        case R.id.signOut: 
            firebaseAuth.getInstance().signOut();
        return true;
    }
    return super.onOptionsItemSelected(item);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    return inflater.inflate(R.layout.fragment_profile, container, false);
}

I want to log out from a fragment. I have three of them with bottom Navigation but the sign out is not happening it should be intent on the LogInActivity.

Please help me out solve this problem.