Final answer:
An outdoor camera in a system functions as a sensor because it detects and sends visual information from its environment. The correct option is A: Sensor.
Step-by-step explanation:
In the given system, the outdoor camera would be considered a sensor. Sensors are devices that detect and respond to changes in their environment. In this case, the outdoor camera detects and captures images or video, which can then be used for monitoring or surveillance purposes. In the system described, an outdoor camera typically serves as a sensor.
A sensor is a device that detects and responds to some type of input from the physical environment. The specific input could be light, heat, motion, moisture, pressure, or any one of a great number of other environmental phenomena. The output is generally a signal that is converted to human-readable display at the sensor location or transmitted electronically over a network for reading or further processing.
Hence, an outdoor camera fits the description of a sensor because it senses visual information from its environment. It does not directly act upon the environment, as an actuator would, nor does it control other devices, which would be the role of a control unit. Therefore, the correct answer for what type of device an outdoor camera is in the system mentioned is Option A: Sensor.