Which of the following is one of the three high angle of attack protections?

The high angle of attack protections in the A320 include mechanisms designed to prevent the aircraft from reaching angles of attack that could lead to a stall. One of these protections is "alpha max," which refers to the maximum angle of attack that the aircraft can safely achieve before stalling. It serves as a critical safeguard by automatically limiting the aircraft's pitch attitude and helping the pilot maintain control, ensuring safe operation even during demanding maneuvers or adverse conditions.

Other options, while related to aircraft handling and performance, do not specifically refer to high angle of attack protections. Roll rate protection and pitch rate protection pertain to the aircraft's handling characteristics in different contexts but are not directly classified under the umbrella of angle of attack protections. "Alpha flap," on the other hand, is a configuration that modifies the wing’s lift characteristics but does not serve the same protective function in preventing stalling. Therefore, "alpha max" stands out as a key element in the system designed to manage high angles of attack.