Final answer:
In English grammar, non-essential parts of a phrase are referred to as 'optionalities'. These parts add detail but are not crucial to the phrase's core meaning. The correct term is 'Optionalities'.
Step-by-step explanation:
In English grammar, the parts of a phrase that are not necessary to convey the basic meaning are typically referred to as optionalities. These are elements that can be added to enrich the information provided but are not essential to the core meaning of the phrase. For instance, in the sentence 'The old, abandoned factory', the descriptions 'old' and 'abandoned' are optionalities that provide more detail but are not required to understand that the sentence is about a factory.
The other options provided are not accurate in describing non-essential elements of a phrase. Inclusions suggest necessary parts, redundancies indicate unnecessary repetition, and elements could be either essential or non-essential parts of a sentence.
For the provided question, the correct answer would be D) Optionalities.