Which type of sensor captures data using passive techniques?

The correct answer is based on the nature of data capture by the sensor. A passive infrared sensor captures data by detecting the infrared radiation emitted by objects in its field of view. It does not actively emit any energy or signals; instead, it relies on the thermal energy naturally produced by objects, including living organisms and other heat sources. This ability to sense the heat emitted makes passive infrared sensors useful for applications such as surveillance and environmental monitoring.

In contrast, radar and laser sensors are active systems that emit signals or energy and measure the reflection or return of those signals to capture data. Electro-Optical sensors also generally function by emitting light and then capturing the reflected light, which constitutes an active technique rather than a passive one. Thus, passive infrared is categorized distinctly, as it operates without generating its own signal, making it the right choice for this question.