This problem is an illustration of the proverb: "In a symmetrical position, play the symmetric point".
White must play in order to live. Any other move fails.
After , White needs both a and b. White can't play two moves in a row, so her group is dead.
White starting a also fails; it the mirror image of .
and make a bent four in the corner shape, killing White. We assume that White can't escape at a.