Graicunas's Formula Is as Follows

Graicunas's formula is as follows: . What does C stand for in this formula?

A) the total number of departments possible in an organization
B) the appropriate number of subordinates a manager can have
C) the appropriate number of levels an organization can have
D) the total number of possible relationships between manager and subordinates
E) the degree of the difficulty in coordinating a certain number of subordinates