The cost basis for the first 100 shares of B stock which you had by exchange of the A shares is $100 or $1 per share of B stock.
The other 100 shares of B stock which you exercised for $0 cost have a cost basis of $0. The 60 shares which vested have a cost basis of $0. You do not claim a loss for the 40 shares which did not vest as your cost basis is $0.
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