Is an adjective referring to someone or something that has special skill practical knowledge especially in a mechanical scientific field. a. Technical c. Validity b. Impetus d. Subtleties?

* Technical refers to skills or knowledge related to a specific field, particularly those involving machinery, science, or engineering.

Let's look at the other options:

* Validity refers to the truthfulness or soundness of something.

* Impetus refers to a force or driving force that causes something to happen.

* Subtleties refer to fine details or nuances.

Only technical directly relates to the specific skill and knowledge in a mechanical or scientific field.