i have to find the value that should be assigned to a property 2

president bought two acres of land for 200,000 then years ago. It is zoned for commercial use however,  it holds eight small single family houses.  a property management firm want to continue to lease the houses and offered 400,000 for the property. A developer wants to build a 12 story apartment on the site and offers 600,000. what value should be assigned to the property