Stan owned machinery which had been acquired at a cost of $250,000. During 2020, the machinery was destroyed by fire. At that time, it had an adjusted basis of $200,000. The insurance proceeds awarded to Stan amounted to $270,000 and he immediately acquired qualifying replacement property for $240,000. What amount of gain should Stan report resulting from the involuntary conversion for 2020?

a. $ 0

b. $70,000

c. $40,000

d. $30,000

e. None of the answers provided is correct

***The answer is D need to know how it was calculated only ? **