Final answer:
The correct answer is option 1) Scanning.
Step-by-step explanation:
The process of a radio receiver that searches several frequencies until the message is completed is called scanning. Scanning is a technique used by the radio receiver to automatically search through a range of frequencies to find and lock onto a specific radio station or signal. It is commonly used in car radios or portable radios that have the ability to search for available stations or signals.
During scanning, the radio receiver quickly tunes into different frequencies, one after another, until it successfully receives a strong and uninterrupted signal. Once a signal is found, the receiver will stop scanning and continue to receive and demodulate the message being transmitted over that specific frequency.
Modulation and demodulation are important processes in radio communication, but they are not directly related to the scanning process. Modulation is the process of encoding information onto a carrier wave, while demodulation is the process of extracting the encoded information from the modulated wave. Transmission refers to the act of sending or transmitting the modulated wave over the airwaves to be received by a radio receiver.