This is the first problem of another set of 4x4 problems. Please find the best result for black! A one point loss will be better (and therefore "RIGHT") than a two point loss, a two point win better than a one point win.
(japanese rules)
(;GM[1]FF[4]CA[UTF-8]AP[CGoban:2]ST[2]
RU[Japanese]SZ[4]KM[0.00]
PW[Weiß]PB[Schwarz]AW[aa][cb][db][ac][bc][dc][ad][bd][dd]AB[ab][bb][cc]C[Black to play - what's the best he can do?!]
(;B[ba]CR[ba]
;W[cd]CR[cd]
;B[ca]CR[ca]C[This jigo is best for black! B C1 instead of B B4 would have been a mistake. RIGHT])
(;B[cd]CR[cd]
;W[bc]CR[bc]
(;B[ca]CR[ca]
;W[bd]CR[bd]
(;B[cc]CR[cc]
;W[ac]CR[ac]C[White wins big.])
(;B[ac]CR[ac]
;W[da]CR[da]
(;B[ba]CR[ba]
;W[ad]CR[ad]C[White wins the capturing race])
(;B[cc]CR[cc]
;W[ba]CR[ba]
;B[ca]CR[ca]
;W[ba]CR[ba]C[Black is lost!]))
(;B[ba]CR[ba]
;W[ac]CR[ac]C[White lives]))
(;B[ac]CR[ac]
;W[bd]CR[bd]
(;B[ba]CR[ba]
;W[ca]CR[ca]C[White lives, black lives not])
(;B[ca]CR[ca]
;W[da]CR[da]
(;B[ba]CR[ba]
;W[ad]CR[ad]C[White wins the capturing race])
(;B[cc]CR[cc]
;W[ba]CR[ba]
;B[ca]CR[ca]
;W[ba]CR[ba]C[Black is dead])))
(;B[ba]CR[ba]
;W[ac]CR[ac]C[White has two eyes])))