Answer: Formal Definition
Step-by-step explanation:
A formal definition is when you provide additional explanations to the meaning. It uses full sentences and defines the thing using big vocabulary and without using slang.
An informal definition uses short sentences, less grammar, simple words, abbreviations, and sometimes figurative language.
An extended definition is usually paragraphs of writing and can use the compare contrast, cause effect, historical references and other stuff to describe the definition.
This definition only uses two sentences, but doesn't use slang or abbreviations to describe it.
Hope that helped a lot.
:)