new WorldType[MAX_PLAYERS]; //We will store the player's world type in this array

#define FREEROAM_ID     0
#define STUNT_ID        1
#define DRIFT_ID        2
#define DM_ID           3

public OnPlayerConnect(playerid)
{
    //Make the player select a virtual world
    ShowPlayerDialog(playerid, 0, DIALOG_STYLE_LIST, "Select World", "Freeroam\nStunt\nDrift\nDM", "Select", "");
    return 1;
}

public OnDialogResponse(playerid, dialogid, response, listitem, inputtext[])
{
    if(dialogid == 0)
    {
        switch(listitem)
        {
            case 0..3: SpawnPlayerInWorld(playerid, listitem); //Call the function "SpawnPlayerInWorld", when the player selects a item on the list
        }
    }
    return 0;
}

stock SpawnPlayerInWorld(playerid, worldid)
{
    switch(worldid)
    {
        case 0:
        {
            WorldType[playerid] = FREEROAM_ID;
            SetPlayerVirtualWorld(playerid, FREEROAM_ID);
            //Add your code here if they selected freeroam
        }
        case 1:
        {
            WorldType[playerid] = STUNT_ID;
            SetPlayerVirtualWorld(playerid, STUNT_ID);
            //Add your code here if they selected stunt
        }
        case 2:
        {
            WorldType[playerid] = DRIFT_ID;
            SetPlayerVirtualWorld(playerid, DRIFT_ID);
            //Add your code here if they selected drift
        }
        case 3:
        {
            WorldType[playerid] = DM_ID;
            SetPlayerVirtualWorld(playerid, DM_ID);
            //Add your code here if they selected DM
        }
    }
    return 0;
}