Reflex actions are involuntary responses to specific stimuli that are mediated by the spinal cord and do not involve conscious thought or decision-making. They are rapid and automatic, allowing for quick responses to potentially harmful or dangerous situations. While most of our body's reactions are reflex actions, there are certain actions that are not considered reflexes.

The correct answer is option 'B' - sweating. Sweating is not considered a reflex action because it is controlled by the autonomic nervous system, specifically the sympathetic division. The autonomic nervous system regulates involuntary bodily functions such as heart rate, digestion, and body temperature. Sweating is a part of the body's thermoregulation process, where the body cools down by releasing sweat onto the surface of the skin. This process is controlled by the hypothalamus, which receives signals from temperature receptors throughout the body and initiates sweating to cool down the body when it becomes too hot. Unlike reflex actions, which involve the spinal cord, sweating is controlled by higher brain centers and is not an immediate response to a specific stimulus.

On the other hand, the other options mentioned - salivation, withdrawal of hand when pinched by a needle, and blinking of eyes - are all examples of reflex actions.

- Salivation: Salivation is a reflex action controlled by the autonomic nervous system. It is triggered by the presence or anticipation of food in the mouth. The salivary glands are stimulated to release saliva, which aids in digestion.

- Withdrawal of hand when pinched by a needle: This is an example of a spinal reflex action called the withdrawal reflex. When the skin is pricked by a needle, pain receptors in the skin send signals to the spinal cord. In response, the spinal cord sends signals to the muscles in the hand to contract, causing the hand to quickly pull away from the source of the pain.

- Blinking of eyes: Blinking is a reflex action that helps protect the eyes from potential harm. When an object comes too close to the eyes or there is a sudden bright light, the reflex arc involving the sensory nerve fibers in the eyes, the facial nerve, and the motor nerve fibers in the eyelid is activated. This causes the eyelids to close rapidly, protecting the eyes from injury or excessive light.

In summary, sweating is not considered a reflex action as it is controlled by the autonomic nervous system and involves higher brain centers, while salivation, withdrawal of hand when pinched by a needle, and blinking of eyes are examples of reflex actions mediated by the spinal cord.