The proposals are black's dilemma: offer only winning fifths and white takes the winning one; offer only bad fifths and white takes the least bad. The engine's own balance command finds 'interesting but fair' points — stones that keep the game alive instead of ending the argument. Two such fifths are on offer here, and neither wins on the spot. You are white at the picking end: choose the one you would rather own. That is renju's answer to the first-move advantage: black proposes, white disposes — black never chooses the battle, white never accepts a lost one.
Choose your fifth to keep.
Finish this step to move on.