Which of the following is a sign of severe dehydration rather than heart failure?

The correct choice reflects a classic sign of severe dehydration, specifically highlighting tachycardia and poor skin turgor. In the context of severe dehydration, the body attempts to compensate for decreased blood volume and can exhibit a rapid heart rate (tachycardia) as a response to hypotension or low blood volume. Poor skin turgor indicates insufficient hydration and loss of skin elasticity, which is particularly associated with dehydration.

In contrast, hypotension and tachycardia can be seen in both dehydration and heart failure, making it less specific. Pulmonary crackles and dyspnea are more indicative of heart failure due to fluid accumulation in the lungs resulting from heart dysfunction. Additionally, peripheral edema and jugular venous distention are hallmark signs of heart failure, associated with fluid overload rather than dehydration, leading to a distinction between these two conditions.