The territory sizes are marked into the board. White gets 6.5 point compensation. Black has captured 4 white stones, and two white stones in board (a) are also dead. White has captured 2 black stones (not visible in diagram). Black has 19 points. White has 20.5 points.
In following problems you need to identify last remaining place, where points could be gained, or reduced. The gained points are marked in the correct answer. The lost reduction opportunities are marked in wrong variations.