A car not engine absorbs 1000 J of heat energy from a reservoir at $\;127^{0}C\;$ and rejects 600 J of heat energy during each cycle .The efficiency of engine and temperature of sink will be :

$(a)\;20\% \;and\;-43^{0}C\qquad(b)\;40\% \;and\;-33^{0}C\qquad(c)\;50\% \;and\;-20^{0}C\qquad(d)\;70\% \;and\;-10^{0}C$