This question is kinda poorly worded IMO. Something you need to remember that if you have a STRONGLY activating group, like NH2, you can get halogenation without a catalyst. However, In my orgo class, my professor told us that you would need an excess of the Cl2, to get di or tri substitution. So if the Br was not in the ortho position, there would have been a tri substitution.
So I think the question should have excess Cl2 to get dicholornation.