What defines 'rotation speed' during takeoff?

Rotation speed during takeoff is fundamentally defined as the speed at which sufficient lift is generated to allow the aircraft to ascend off the ground. This moment typically occurs when the pilot pulls back on the control column, causing the aircraft's nose to rise. At rotation speed, the angle of attack is optimal for generating lift to overcome the weight of the aircraft, which is a crucial phase during the takeoff sequence.

Understanding this concept is essential for flight safety and performance. The other options refer to different aspects of flight operations. For instance, the minimum speed for taxiing is associated with ground movement, while the top speed reached during flight relates to cruise performance, and cruising speed altitude pertains to the operational phase once the aircraft is in the air. Therefore, option B accurately captures the significance of rotation speed in the context of takeoff.