Answer: B. $60,000 capital gain
Explanation: The land being sold at the rate of $160,000 having a book value of $100,000 will make Paul the owner realise a gain on the sale of the asset of $60,000 (capital Gain)
The gain on the land is a capital gain to Paul as he held the land for investment purpose before selling the land to the partnership business he has a 60% capital interest in.
To Paul, the gain is a Capital gain to him as he owns the asset wholly before selling it to the partnership business which is a real estate business .