Donald and his significant other, Donna, owned vacant land zoned for commercial developement. They held title to the property as joint tenants. Each contributed $300,000 of the $600,000 purchase price. Donald died recently when the property had a FMV of $1,300,000. For estate tax purposes only, the IRS would presume the value of Donald's interst in the property at his death was how much? a. $300,000 b. $600,000 c. $900,000 d. $1,300,000