Final answer:
Reduced/Flex thrust for takeoff is not authorized when the aircraft is heavily loaded, the temperature is high, and the runway is contaminated. Hence the correct answer is option 4
Step-by-step explanation:
The use of Reduced/Flex thrust for takeoff is NOT authorized when all of the above conditions apply: the aircraft is heavily loaded, the temperature is high, and the runway is contaminated.
Hence the correct answer is option 4