Final answer:
A musician's medium refers to how they express their musical ideas. In this case, a song is considered the musician's medium as it includes elements like melody, harmony, and lyrics.
Step-by-step explanation:
A musician's medium refers to the means or vehicle through which they express their musical ideas. In this case, out of the given options, the item that would be considered a musician's medium is Song. A song is a composition of music that includes elements such as melody, harmony, and lyrics. Musicians use songs to convey their artistic expression and connect with their audience.
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