I erased system field accidentally! How do i get an old listing Field back?

hi guys,

i accidentally erased a system field in Listings>Listing Field>Property for (Key: sale_rent). it originally was radio button option which is used on search at the home page (All-Sale-Rent).

i wanted to make it dropdown menu so i erased a System Radio Button Field. now i have Dropdown Menu field which is not connected to Add listing or any other option which could function exactly as the old one. thus search engine cannot find properties which are on Sale or Rent.

can anyone here help me how do i connect this field menu as it was before?

thx in advance