Notwithstanding the provisions of paragraph (1), the Commissioner of Social Security shall not require the disposition of any real property for so long as it cannot be sold because (A) it is jointly owned (and its sale would cause undue hardship, due to loss of housing, for the other owner or owners), (B) its sale is barred by a legal impediment, or (C) as determined under regulations issued by the Commissioner of Social Security, the owner’s reasonable efforts to sell it have been unsuccessful.