It Is Useful to Think of Physical Capital in Terms

It is useful to think of physical capital in terms of a variable, .

A) stock; because most equipment is solidly built.
B) flow; because its usefulness lasts over a long period of time.
C) flow; because it is usually put in place and maintained over a long period of time.
D) stock; depending on the context.
E) stock; because any flow of investment adds to the current capital stock.