You wouldn't be able to take 1B03 unless you are in a music program. The two music history courses available for non-music majors are 1A03 and 1AA3.
1A03 covers Medieval to Baroque eras and 1AA3 covers Classical to Modern music. So it just depends on what music you find more interesting - Gregorian Chant, Bach, Handel, etc. or Mozart, Beethoven, Stravinsky, etc.
I personally find Classical and Modern music much more interesting to study, but I know a lot of people who really hate 20th century and modern music. So it really is personal preference
Though if you don't have a lot of background knowledge, a lot of people are more aware of the classical era and therefore that might be more interesting to you.
