Efficiency of carnot engine can increase by increasing sink temperature compaire to increase source temp proof | full explanation

 Efficiency of carnot engine can increase more by increasing sink temperature compare two increasing source temperature

Proof

Hair we can see that the rate of change of efficiency with respect to you sink  temperature is more as compared to the rate of change of efficiency with respect to to source temperature so

So from the above conclusion we can say that 

Efficiency of carnot engine can be increased by increasing sink  temperature as compared to increase in source temperature