I'm using modal and I just want to use dropdown select method in laravel 7 - laravel-7

Question

This is my code in my Controller but I already try this method without using modal and it works.
public function create()
{
$department = Department::pluck('department', 'id');
return view('positions.create',compact('department'));
}
public function store()
{
$validator = Validator::make(Request::all(), [
'dep_id' => 'required',
'position' => 'required',
],
[
'dep_id.required' => 'Department Required',
'position.required' => 'Position Required',
]);
if ($validator->fails()) {
return redirect()->back()
->withErrors($validator)
->withInput();
}
Position::create(Request::all());
Session::flash('message', 'Position Created Successfully');
return redirect()->back();
}
This is my Model:
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Position extends Model
{
protected $guarded = [];
public function department(){
return $this->belongsTo('App\Department','dep_id','id');
}
}
This is my code in my create modal form, but I get this error:
Undefined variable: department
I want to use the modal form for my project.
<div class="modal-body">
#include('alert')
{!! Form::open(['method'=>'POST','action'=>'PositionController#store']) !!}
<div class="form-group">
<label>Department</label>
{!! Form::select('dep_id',$department,null,['class'=>'form-control','placeholder'=>'PLEASE SELECT']) !!}
</div>
<div class="form-group">
<label>Position</label>
{!! Form::text('position',null,['class'=>'form-control']) !!}
</div>
<div class="text-end">
<button type="submit" class="btn btn-primary">Submit</button>
</div>
{!! Form::close() !!}
</div>