A person’s
"transfer date" for residential land or vacant land is the date the person is
entitled to possession of the land under the dutiable transaction that is—
(a) the transfer, or agreement for the transfer, of the land; or
(b) the acquisition, mentioned in section 85 (b) , of a lease of the land; or
(c) the vesting, mentioned in section 85 (c) , of the land.