Which type of css style is best used to format only a single element on a single page in a site?

Inline CSS is the answer you're looking for, and is generally not good practice to use consistently, as it creates a lot of unnecessary clutter and mess. Prefer external CSS, or at the very least internal CSS.

Inline CSS is when you modify the element itself, rather than selecting classes, IDs and elements like you would with internal or external CSS.

The follow HTML and CSS would cause the paragraph to have red text:

<p style="color:red">
Hello World!
</p>

Learning about them i guess, idk

Metaprogramming  is a programming technique in which computer programs have the ability to treat programs as their data. it means that a program can be designed to read, generate, analyse or transform other programs, and even modify itself while running. ps: you don't have any options there.