With the increase in pressure ratio thermal efficiency of a simple gas turbine Plant with fixed turbine inlet temperature

Gas turbine engines and airbreathing jet engines use the Brayton Cycle. ... air and fuel mixture is then ignited in an expansion cylinder and energy is released, ... increase in the gas turbine inlet temperature for two different pressure ratio values. ... with thepressure ratio (thus the thermal efficiency) and the net work output.

The logical conclusion would be C

Thank you Eng.Alex, the Q is out of my major

Thank you for invitation ...

the Q is out of my major..

I believe the answer is choice "C"

Thanks for invitation 

Agree with the majority

C first increases and then decreases. 

Option C