What is the name of the boundary - akin to a parallel of latitude - that separates north from south township locations (e. g. T1N north of this boundary and T1S south of this boundary)?

A. The boundary is known as a base line.

B. The boundary is known as a principal meridian.
C. The boundary is known as a range line.
D. The boundary is known as a "local equator."
E. The boundary is known as a "local prime meridian.