Final answer:
Heat activation is not recommended for smoke removal systems because it can delay the activation until the fire is more advanced, while automatic and smoke detection activations provide a quicker, more responsive system initiation.
Step-by-step explanation:
The activation method not recommended for smoke removal systems is c) Heat activation. Smoke removal systems are intended to operate as soon as the presence of smoke is detected to prevent the spread of fire and facilitate evacuation. Heat activation is less ideal since it typically requires a higher temperature to trigger, potentially delaying the activation of the smoke removal system until much later in the fire event. Automatic and smoke detection activations are preferred because they can quickly sense the presence of smoke and start the system, providing immediate assistance in maintaining a safer environment. Manual activation is also essential for allowing human intervention to control the system as needed.