Low light SLR
In addition to what the guys said, you need a "good" low light sensor to produce quality images with the least possible noise and much details and among your chosen bodies the D7100 is a good compromise unless you wanna spend a fortune on a top end FF body and a lens.
|Douaumont Ossuary by Eric 54-BNF|
from Armistice Day
|Silhouette at sunset by Jill Hancock|
from Portrait Lens (around 80mm or equivalent - please check the full rules)