The underlined portion of: Hypertension (orthostatic, benign, simple) identifies a(n);

The term "Hypertension (orthostatic, benign, simple)" highlights that "orthostatic, benign, simple" serves to provide additional context about the type of hypertension. In medical terminology, nonessential modifiers are descriptive terms that enhance the main term but do not change the fundamental meaning of that term. They can be omitted without altering the overall understanding of the condition.

In this case, "orthostatic," "benign," and "simple" are variations of hypertension that specify its characteristics but are not essential to identifying the primary condition. Conversely, essential modifiers would be critical to understanding the specifics of the condition, which is not the case here as removing them would still leave the main term understood. Thus, the underlined portion exemplifies a nonessential modifier.