Final answer:
The subject of this question is Mathematics. It asks about the encoding of a Spotify Code using Gray code and the number of bits required for a code with 3 bars. Each bar is represented using 3 bits.
Step-by-step explanation:
The subject of this question is Mathematics. The question pertains to the encoding and representation of a Spotify Code using Gray code. It asks how many bits are required to encode a Spotify Code that consists of 3 bars. The question also mentions that the first and last bars serve as reference points.
In this case, the Spotify Code is represented using Gray code, which is a binary code where consecutive values differ by only a single digit. Since there are 3 bars, or 9 bits in total when encoded using Gray code, this means that each bar is encoded using 3 bits.
Therefore, the subject of this question is Mathematics and it is suitable for High School students.