Answer:
$190,000
Step-by-step explanation:
If I decide to use my house as a professional office, the value or cost is the opportunity cost which implies the benefit of a forgone alternative.
The house was purchased for $89,000 and rent of $1200 is being received for many years, so we can assume that the cost of purchasing the house has been fully recovered. So the opportunity cost here is the current market price of the house.
Current value = $210,000
Selling expenses = $20,000
Opportunity cost = 210000 - 20000 = $190,000