Lease option agreement on office building

[Robin Suh]

I have a small office building in California and someone offered to lease the property from me for 3 years with an option to purchase. 

Some questions for anybody with experience with this:

-how much above market price do I sell the property for since it can potentially be 3 years down the line?

-how do I price the lease payment?

-what is the typical deposit amount I should charge?