Before ATMs, the Average Bank Branch Employed 20 Employees; After

Multiple Choice

Before ATMs, the average bank branch employed 20 employees; after ATMs, the average branch employed 13 employees, but banks have opened more branches. These developments suggest that

A) ATMs are purely substitutes for labor in banking.
B) labor and ATMs are substitutes in some bank functions, complements in others.
C) ATMs are purely complements for labor in banking.
D) labor and ATMs are neither substitutes nor complements in banks' various functions.