A. Close to that of one key
B. The Specified separation is sloppy
C. Intermediate between keys
D. Intermediate one key
I had been asked this question by my college director while I was bunking the class.
This intriguing question comes from Reflux Stage Relationships topic in division Column Process Design, Optimization and Shortcut Calculations of Distillation Design
For explanation: For distributed systems the Specified separation is sloppy, while for the distributed system it is close to that of one key.