XML Serializer - advanced features of a serializer (C#)

This is my current code:

List<Tile> listTiles = new List<Tile>();

for (int i = 0; i < Width; i++)
for (int j = 0; j < Height; j++)
{
    //Load each tile into the list
    listTiles.Add(mapbox.RenderedMap.Tiles[i, j]);
}

XmlSerializer serializer = new XmlSerializer(listTiles.GetType(), new  XmlRootAttribute("Map"));
StreamWriter writer = new StreamWriter(@"savedmap.xml");
serializer.Serialize(writer.BaseStream, listTiles);

What it basically does is it loads every current tile onto a list, which is then serialized in the format:

<Map>
    <Tile>TileData</Tile>
</Map> 

With Map being the root node.

My question is: How can I make it so instead of what I have now, I have the following?

<GameSave>
    <Map>
        <Tile>TileData</Tile>
    </Map>
    <Options>
    </Options>
</GameSave>

So basically, add a root node and put my Map node into it (which contains the Tile nodes), alongside an options node. Would I have to change the way im doing it and not use a list since, the list only contains tiles?