GUI manager persistent prefs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class GUIManager : MonoBehaviour {

    public GameObject MainMenu;
    public GameObject OptionsMenu;
    public GameObject Options;
    public GameObject Gameplay;

    public AudioControl audioControl;

    public void Start()
    {
        float existingMaster = PlayerPrefs.GetFloat(audioControl.MasterVolume, 1f);
        float existingMusic = PlayerPrefs.GetFloat(audioControl.MusicVolume, 1f);
        float existingSFX = PlayerPrefs.GetFloat(audioControl.SFXVolume, 1f);

        audioControl.SetMasterLevel(existingMaster);
        audioControl.SetMusicLevel(existingMusic);
        audioControl.SetSfxLevel(existingSFX);
    }


    public void MainToOptions()
    {
        MainMenu.CrossFade(OptionsMenu);
    }

}