What system contributes to generating the beta rhythm during vigilance?

The reticular activating system plays a crucial role in generating the beta rhythm, particularly when a person is in a state of vigilance or alertness. This system is a network of neurons located in the brainstem that is essential for regulating arousal, attention, and consciousness. When we are alert, the reticular activating system promotes the activation of various regions of the brain, leading to increased levels of beta waves in the electroencephalogram (EEG). These beta waves, associated with active thinking, problem-solving, and focused tasks, typically occur in the frequency range of 13-30 Hz.

While the peripheral nervous system, somatic nervous system, and central nervous system all play roles in various bodily functions and responses, it is the reticular activating system that specifically mediates the changes in brain wave activity associated with alertness and vigilance. Therefore, it is directly responsible for the generation of the beta rhythm, making it the correct choice for this question.