Process variation that are intrinsic to the process are:

A) common,nonassignable causes of variation.
B) special or assignable causes of variation.
C) prevention costs.
D) internal failure costs.
E) external failure costs.

Intrinsic (or natural) process variation refers to the common causes of variation that are inherent to the process itself, and cannot be attributed to any specific factors or events (i.e. nonassignable causes). Examples might include fluctuations in temperature or humidity, wear and tear on machinery, or natural variations in materials or inputs. These types of variation are expected and normal, and can often be managed through statistical process control methods.