Objects in the image:
category: skateboard
category: skateboard
category: person
category: person
category: skateboard
category: skateboard
category: person
category: person
category: person
category: backpack
category: person
category: person
category: person
category: person

Guessing-game dialogue about one of the objects:
q: is it person?
a: Yes
q: one among 5 roller skating?
a: No
q: lady in the back with blue shirt?
a: Yes