C#: Thread safe function
<p>which of the following code is more appropriate situation where  multiple threads access the function</p>

<pre><code>public ArrayList CallMe1()
    {
        ArrayList al = new ArrayList();

        lock(al.SyncRoot)
        {
            al.Add("33");
            al.Add("45");

            return al;
        }

    }

    public ArrayList CallMe2()
    {

        ArrayList al = new ArrayList();

        Monitor.Enter(al);

        al.Add("33");
        al.Add("45");
        Monitor.Exit(al);

        return al;


    }
</code></pre>
