What is one of the factors that prohibits reduced thrust takeoffs?

The correct choice is based on the operational procedures regarding the safety of takeoffs in proximity to other aircraft. When performing a takeoff, particularly in close quarters with a heavy aircraft ahead, there is an increased risk of wake turbulence, which can adversely affect lift and control during the takeoff roll and initial climb. Reduced thrust takeoffs require more careful management of aircraft performance, especially regarding climb capability and speed. Therefore, in such scenarios, full thrust is advisable to ensure optimal performance, especially in the event of needing to abort the takeoff or in the presence of unexpected disturbances.

In contrast, having clear skies, sufficient runway length, or temperatures above freezing do not inherently create safety concerns linked to reduced thrust takeoffs. These other factors may even support a standard or reduced thrust operation under different conditions, making them less critical compared to the situation involving heavy aircraft and wake turbulence.