Which of the following symptoms is associated with the "stress cocktail" generated by the Sympathetic Nervous System?

The correct choice highlights the body's response to stress through the activation of the Sympathetic Nervous System, which prepares the body for a "fight or flight" situation. When the Sympathetic Nervous System is activated, a variety of physiological changes occur to enhance alertness and readiness to respond to perceived threats.

Increased alertness stems from the release of stress hormones such as adrenaline, which heightens senses and cognitive functions, allowing an individual to react more quickly and effectively. This state of heightened awareness is critical in situations requiring quick decision-making or physical action.

The other symptoms mentioned do not match the physiological responses associated with the "stress cocktail." For instance, decreased muscle tension signifies a state of relaxation, while a lower heart rate and dilated blood vessels typically reflect the activity of the Parasympathetic Nervous System, which counters the stress response rather than promoting it.