I really didn't intend it to be a trick question. I'll admit it might be a koan though I'm not sure what technically makes a question a koan...so. Your answer is quite interesting however. Certainly not ordinary.
If a brain then a mind is a mental consruct....
I don't consider the brain to be mind or the generator of mind. I view mental constructs as coming from mind so I don't know if I could consider mind itself a mental construct. I can't rule that out though, my understanding is not refined enough to, but probably not. I do see brain as a mental construct.
If a spirit then a mind is a spiritual construct and brain is a mirror..
To me spirit is just understanding/awareness itself. Mind is just a reflection in the mirror and the mirror is the ground or the true nature of reality. Pure awareness beyond conceptualizations. So I would have to say that spirit is the mirror and mind is just a reflection.
I see brain as just a squishy computer that runs the body. A really really impressive computer though if just a touch glitchy and more than a tad dangerous. ; )
So, to sum that all up, I do see mind as a construct. Or put another way; a conceptual reflection of the non-conceptual reality that underlies everything. I guess that means that I haven't perfectly agreed with either of your possible views of mind so I can't pin you to either one and ask you to answer on that basis. Guess I'll just have to continue contemplatin' it on my lonesome. :^(