$5\mathrm{.}16$ WP A power cycle operating between hot and cold reservoirs at $500$ K and $300$ K $,$ respectively, receives $1000$ kJ by heat transfer from the hot reservoir. The magnitude of the energy discharged by heat transfer to the cold reservoir must satisfy $($a$)Q_C>600kJ,($b

$($c$)Q_C=600kJ,($d$)Q_{C}600kJ.$