B. sale of a portion of a tract under sales contract, if the right to purchase the portion is derived from an assignment made on or before September 4, 1956; or
C. sale of a portion of a tract under sales contract, or under a contract entered into in substitution of such contract, if the right to purchase all other portions of the tract were assigned or relinquished on or before September 4, 1956 by the person holding the contract. The legislature may enact laws to carry out the purposes of this amendment.
