Translation:If you were me, you would visit which museum in Paris?
I also answered "À ma place, tu visiterais quels musées à Paris" for the dictation exercise. Rejected 2021-07-03. I wasn't expecting the liaison to be required here, and can't see what else would make it sound different to the singular version. I'll report it as "should have been accepted" but I'm willing to be corrected!
Why not accept the plural? À ma place tu visiterais quels musées à Paris ? That's a reasonable question; the city is one of the best in the world for musuems.
It would sound the same unless you made a liasion from musées to à, but I thought that was optional or prohibited.