Final answer:
The system with zero entropy is Zero K, pure system, a crystal.
Step-by-step explanation:
The system with zero entropy is Zero K, pure system, a crystal. This is because the entropy of a pure, perfect crystalline substance at 0 K is zero, according to the Third Law of Thermodynamics. At absolute zero, the particles in a crystal are in fixed positions and exhibit no motion, resulting in a single microstate and zero entropy.