The productivity of labour does not depend only on its own effort and efficiency, but also on?

I. the level of technical knowledge

II. the quality of other factors

III. racial qualities that allow persons from certain races to have good physique and be very active.

A. I only
B. I and II only
C. I and III only
D. II and III only
E. III only

Correct Answer:

Option B – I and II only