how do transaction recovery procedures use the deferred-write and write-through techniques to recover transactions

Brody and tanya recently sold some land they owned for $150,000. they received the land five years ago as a wedding gift from brody's aunt jeanette. she had already given them cash equal to the annual exclusion during that year. aunt jeanette purchased the land many years ago when the property was worth $20,000. at the time of the gift, the property was worth $100,000 and aunt jeanette paid $47,000 in gift tax. what is the long term capital gain on the sale of the property