Asrecentlyas1950,tuberculosiswasnevercurableunlesssequesteredinsanitariums;today,thedrugIsoniazidhasmadesuchtreatmentobsolete.（）
(A)unlesssequestered
(B)withoutsequestering
(C)withoutbeingsequestered
(D)unlessitwassequestered
(E)unlesspatientsweresequestered