Final answer:
The most popular audio file format among the given options is d) MP3. MP3 files compress audio data, allowing for smaller file sizes without significant loss in audio quality, making them easy to share, download, and stream over the internet.
Step-by-step explanation:
The most popular audio file format among the given options is MP3. MP3 stands for MPEG-1 Audio Layer 3 and is widely used for storing and playing music files. MP3 files compress audio data, allowing for smaller file sizes without significant loss in audio quality. This makes them easy to share, download, and stream over the internet.
RA (RealAudio) is a format developed by RealNetworks for streaming audio over the internet but is not as commonly used as MP3.
WAV (Waveform Audio File Format) is a lossless audio format that is widely supported by different operating systems and software, but it is not as popular as MP3 due to larger file sizes.
WMA (Windows Media Audio) is a proprietary format developed by Microsoft. While it was popular at one time, it has become less common compared to MP3.