On the topic of NUA, what happens to the LTCG on NUA value if the stock depreciates after distribution ?

For example, if the total value was $100000 with a cost basis of $20000 at the time of LSD and the total value drops to $50000 at the time of sale after a few years, is LTCG owed on

a) $80000 ($100000 – $20000)

or

b) $30000 ($50000 – $20000)

Thanks !