C# - closing Sql objects best practice

Question

If you have a C# function with Sqlaccess, is it mandatory to close all objects/handles, or is everything cleaned up automatically once you exit the function

For exam

Answer 1

Explicit disposing in the finally statement is another approach, although the using statement is a much better solution. It produces a bit more code, but demonstrates the goal...

SqlConnection conn = null;
try
{
    //create connection

    SqlCommand cmd = null;
    try
    {
        //create command

        SqlDataReader reader = null;
        try 
        {
            //create reader
        }
        finally
        {
            reader.Dispose();
        }
    }
    finally
    {
        cmd.Dispose();
    }
}
finally 
{
    conn.Dispose();
}