The commonly used lime in white washing, is

ANS:B - fat lime

Fat lime is also known as high calcium lime or pure lime or rich lime or white lime. It is popularly known as fat lime as it slakes vigorously and its volume is increased to about 2 to 2.5 times that of quick lime. This lime is used for various purposes as whitewashing, plastering of walls, as lime mortar with sand for pointing in masonry work, as a lime mortar with turki for thick masonry walls, foundations, etc.