NullReferenceException

public class Basket : MonoBehaviour
{
    private Text _score;
    private HighScore _highScore;
 
    private void Start()
    {
        _highScore = GetComponent<HighScore>();
 
        GameObject _scoreObject = GameObject.Find("ScoreCounter");
        _score = _scoreObject.GetComponent<Text>();
        _score.text = "0";
    }
 
    void Update()
    {
        Vector3 mousePosition2D = Input.mousePosition;
        mousePosition2D.z = -Camera.main.transform.position.z;
 
        Vector3 mousePosition3D = Camera.main.ScreenToWorldPoint(mousePosition2D);
 
        Vector3 position = transform.position;
        position.x = mousePosition3D.x;
        transform.position = position;
    }
 
    private void OnCollisionEnter(Collision collision)
    {
        GameObject apple = collision.gameObject;
 
        if (apple.CompareTag("Apple"))
        {
            Destroy(apple);
 
            int score = int.Parse(_score.text);
            score += 5;
            _score.text = score.ToString();
 
           if (score > _highScore.Score)
                _highScore.Score = score;
        }
    }
}

public class HighScore : MonoBehaviour
{
    private int _score = 100;
    private Text _text;
 
    public int Score { get { return _score; } set { _score = value; } }
 
    private void Start()
    {
        _text = GetComponent<Text>();
    }
 
    private void Update()
    {
        _text.text = "HighScore: " + _score;
    }
}

public HighScore ReturnHighScore()
{
    return _highScore;
}