In a gas turbine cycle, the turbine output is \(600 \mathrm{~kJ} / \mathrm{kg}\), compressor work is \(400 \mathrm{~kJ} / \mathrm{kg}\) and heat supplied is \(1000 \mathrm{~kJ} / \mathrm{kg}\). The thermal efficiency of the cycle is:

(a) \(80 \%\)

(b) \(60 \%\)

(c) \(40 \%\)

(d) \(20 \%\)