Actually, they are not. Bop is from a slightly later era than bebop. Art Blakey is from the late 50s, while Bird played with Dizzy much earlier in the 40s.
The band Chicago also has albums titled 19 and 21. And they were inducted into the Rock and Roll hall of fame this year, so they are certainly well-known enough to be an obvious answer for old people to come up with.
Plus, if the answer was Chicago, then La bohème would be an operc, and Misters Vedder's and Van Halen's first name would be "Oddie" (which, actually, I kinda like!).
5 years since my last complaint and it is still ridiculous that there is a Macklemore question on this quiz. He's in the same tier of irrelevancy Marky Mark and the Funky Bunch.
The question could be improved a little. Like you said, a chord can be two notes (like an open fifth), and for me, "together" is not quite specific enough, since "together" could mean subsequently rather than simultaneously. "Multiple notes played simultaneously" without mentioning number would be better, I think.
A note on the definition of chord: it's true that at least one dictionary defines it as "three or more musical tones sounded simultaneously". But an open fifth is generally discussed in music theory as a chord (e.g., from Wikipedia:, emphasis mine: "A bare fifth, open fifth or empty fifth is a chord containing only a perfect fifth with no third."). Another name for this is "power chord"--it's right there in the name!
Macklemore solo however released "The language of my world" as far back as 2005.
i suggest just saying a group of chords played together typically in the harmony
A note on the definition of chord: it's true that at least one dictionary defines it as "three or more musical tones sounded simultaneously". But an open fifth is generally discussed in music theory as a chord (e.g., from Wikipedia:, emphasis mine: "A bare fifth, open fifth or empty fifth is a chord containing only a perfect fifth with no third."). Another name for this is "power chord"--it's right there in the name!