Which of the following is a sign of shock?

The presence of a rapid, weak pulse is a classic sign of shock and indicates that the body's circulation is compromised. In shock, the body attempts to compensate for a decrease in blood volume or blood flow by increasing the heart rate; however, as shock progresses, the pulse may become weak because the heart is not pumping adequately due to reduced blood circulation or low blood pressure.

This option aligns with the physiological changes that occur in shock, where critical organs are not receiving enough oxygen-rich blood, leading to compromised function and a weak pulse while still maintaining a fast heart rate.

The other options reflect conditions that are inconsistent with shock. Warm and dry skin suggests that the body is not in a state of shock, as shock often leads to cool, clammy skin due to vasoconstriction. Normal blood pressure would typically indicate adequate perfusion, contradicting the situation where someone is in shock. Lastly, a sluggish response to stimuli could be a sign of a more advanced state of shock or other serious conditions, but it is not as direct an indicator as a rapid, weak pulse. Thus, the rapid, weak pulse serves as a clear indication of shock, making it the correct answer.