Objects in the image:
category: backpack
category: bottle
category: person
category: bottle
category: person
category: person
category: sports ball
category: person
category: person
category: backpack
category: person
category: person
category: person

Guessing-game dialogue about one of the objects:
q: is it a person?
a: No
q: is it the volleyball?
a: No
q: is it the net?
a: No
q: is it the table in the back middle?
a: N/A
q: is it blue?
a: N/A
q: is it the air conditioner in the wall?
a: No
q: is it a chair?
a: No
q: is it something someone is wearing?
a: No
q: is it the mirrored rectangle?
a: No
q: is it the bench?
a: No
q: is it a part of the wall?
a: No
q: is it the floor?
a: No
q: is it a piece of equipment?
a: No
q: is it sitting on the table?
a: No
q: is it sitting on the blue thing on the floor on the right?
a: No