Final answer:
Among the choices listed, 'lolling tongue' is not a sign of canine stress; it's a behavior indicating relaxation or the need to cool down.
Step-by-step explanation:
The one that does not usually signal stress is D. Lolling tongue. This is typically a sign of a relaxed state, overheating, or a need to cool down, rather than stress. Shaking off can be a sign of trying to release tension, scratching could be due to discomfort or nervousness, and grooming could be a self-soothing behavior when a dog is stressed.