The correct answer is D. Protolanguage
Explanation:
In linguistics which is the study of language, a "protolanguage" is a language, which in most cases has not been proven but it is hypothesized, that is attributed to be the language that led to other languages due to evolution in language and historical processes of human societies. This means the proto-language is the ancestor of other languages and because of this, languages derived from one proto-language often share common traits. Therefore, a hypothesized ancestral language that leads to two or more languages is a Protolanguage.
An email is a digital way of sending a message, through the internet, online. :)
