Opaque bodie

I am at the behest of somebody else to deliver this chemistry question to the denizens of /sci/. Please answer truthfully.

"Any body, which is opaque, will produce a peaked spectrum of photons called ______"

A) ultraviolet rays.
B) a blackbody spectrum.
C) gamma rays.
D) infrared rays.
E) microwaves.

B is the only answer that makes sense (the other answers are temperature dependent: infrared at low temperatures, gamma at uber temperatures), though it's not a very satisfying answer.  A perfectly reflecting mirror is "opaque" since you can't see through the object, but I think such an object would have 0 blackbody radiation.