How delete options from the dropdown gui withscript?

Heyho, I mage a GUI where u got some buttons if u hit one a list of gameobjects are loaded from resources and a dropdown menu is filled with option. Now I got to my problem. How Can I delete the dorpown.options which are curently created ? I tried .ClearList but this doesnt work any Ideas?

Here is a lil bit of my code which is relevant to this problem:

       public void LoadShopsSpec()
     {
    
         _dropdown.gameObject.SetActive(true);
         SpawnPlaceHouse = ShopSpec;
         string ShopsSpec = "ShopsSpec";
         InitGui(ShopsSpec);
     }
     public void LoadShopsCorner()
     {
         _dropdown.gameObject.SetActive(true);
         SpawnPlaceHouse = ShopCor;
         string ShopsCorner = "ShopsCorner";
         InitGui(ShopsCorner);
     }
 
 
 
   void InitGui(string BuildingType)
     {
      if(_buildings != null)  Array.Clear(_buildings, 0, _buildings.Length);
         _buildings = Resources.LoadAll<GameObject>(BuildingType);
    
         foreach (GameObject buil in _buildings)
         {
             GameObject buils = buil.gameObject;
             string building_ = buil.name;
             _buildingsname.Add(building_);
           
         }
         foreach (string c in _buildingsname)
         {
             
             _dropdown.options.Add(new Dropdown.OptionData() { text = c });
             
         }
     }