Which of the following symptoms is indicative of hypokalemia?

Hypokalemia, or low potassium levels in the blood, is known to cause a variety of symptoms, particularly related to muscle function. Muscle cramps are a classic manifestation of hypokalemia due to the critical role potassium plays in muscle contraction and nerve function. When potassium levels are insufficient, it can lead to increased neuromuscular excitability and result in cramps or spasms.

The other options listed, while they can certainly be bothersome, do not specifically indicate hypokalemia. Severe headaches and mood swings may occur due to a wide range of conditions, such as dehydration, stress, or other electrolyte imbalances, but they are not specifically linked to low potassium levels. Similarly, loss of coordination can arise from numerous neurological or metabolic issues and is not a hallmark symptom of hypokalemia. Therefore, muscle cramps stand out as the specific symptom directly indicative of hypokalemia.