question: What is the typical architecture of a WSN (wireless sensor network) node? option 1: Only a sensor unit option 2: Only a processor and a radio transceiver option 3: Only a sensor unit, a processor and a radio transceiver option 4: Only a processor, a radio transceiver, and a power supply option 5: A sensor unit, a processor, a radio transceiver, an A/D converter, a memory unit, and a power supply 