Which of the following is a sign of shock?

An increased heart rate is a well-documented physiological response to shock. When a person is in shock, the body is attempting to maintain adequate blood flow and oxygen delivery to vital organs despite a compromise in the circulatory system, which can result from factors like blood loss, dehydration, or severe infection.

To compensate for low blood pressure and insufficient blood volume, the heart beats faster in an effort to pump more blood and improve tissue perfusion. This compensatory mechanism can be an early indicator of shock. By contrast, stable blood pressure typically indicates that the body is not experiencing an acute crisis, while warm, dry skin is often associated with conditions such as heat-related illnesses or certain types of shock (like neurogenic shock) where the skin may feel warm due to vasodilation. Clear, responsive speech suggests that the patient is alert and oriented, which is not compatible with the confused or altered mental status seen in significant shock scenarios.

Therefore, the presence of an increased heart rate serves as an important clinical sign indicating that the body is attempting to compensate for an underlying issue related to shock, making it the correct answer.