An invontor claims to have invontod a heat engine that oporates using enorgy rosorvoirs whoso temporatures aro 600 K and a 300 K. Sho also claims that this engine produces 10 kW ol power whilo rejecting hoat at a rate of 5 KW. Wnat Is the limit on the ongino's thormal efficoncy
a.0.3
b.0.7
c.0.5
d.01