Easy one. My answer is A.
As ambient temperature rises, your air density decreases.
The gas turbine engine's Fadec or HMU will try to maintain an ideal mixture between air and fuel. If your air density decreases, the fuel flow needs to decrease to maintain this balance and squeeze the most juice out of your engine.
It doesn't say from where the ambient temperature rises so it's possible that the rise occurs within the temperature range where N1 is limited by OAT. If your N1 is already OAT temperature limited, an increased fuel flow will result in you going beyond the N1 and EGT limit for given temperature and cause damage to your turbine.
Result is, fuel flow for max thrust/power decreases in all cases of increasing ambient temperature so B and C are wrong.
Last edited by fly_antonov; 30th Dec 2010 at 18:26.