Final answer:
The syllable 'ut' in musical solmization has been replaced by 'Do,' which is now the first note of the scale. Mnemonic devices like 'Every good boy does fine' are often used to remember the musical notes on the lines of the treble clef. Perfect or absolute pitch is a rare ability to identify musical notes by ear without any reference.
Step-by-step explanation:
The 'ut' used to be the first or key note of the musical scale in the solmization system; this has been replaced by the syllable 'Do.' Therefore, the correct answer to the question of what has replaced 'ut' is a) Do. In musical education, different mnemonic devices are used to remember various elements of music theory. For example, the phrase "Every good boy does fine" helps students recall the notes E, G, B, D, and F which correspond to the lines of the treble clef. It's worth mentioning that musical notes like A-sharp, C, or E-flat are the foundational elements of a song. Some individuals have a unique ability known as perfect or absolute pitch, which allows them to identify musical notes just by ear.