Which of the following is a sign of poisoning?

Slurred speech is a well-known symptom associated with poisoning, particularly when it involves substances that affect the central nervous system, such as alcohol or certain drugs. The impairment in speech clarity occurs because the nervous system, which controls muscle movement and coordination, is affected by the toxic substance. This can lead to difficulties in articulate speech, often giving an impression of being intoxicated.

The other options represent signs or symptoms that do not typically correlate with poisoning. Increased energy might suggest that a person is alert and unaffected, which contradicts the lethargic or impaired state often seen in poisoning cases. Clear skin generally indicates good health, while bright red cheeks might suggest flushing or other reactions that can occur with different conditions but are not specific indicators of poisoning. Understanding the implications of these symptoms helps in recognizing potential cases of poisoning more effectively.