The arc-to-node ratio is given as r = a/n. What does ‘a’ represent in the ratio ?

The arc-to-node ratio is given as r = a/n. What does ‘a’ represent in the ratio ?

A. maximum number of nodes at any level
B. longest path from the root to a leaf
C. number of modules
D. lines of control

Explanation: ‘a’ represents the arcs or the lines of control.