Which of the following is a basic word part that comes from another language?

A. affix
B. root
C. suffix
D. prefix

B. root

The correct answer is D. prefix.

A prefix is a basic word part that is added to the beginning of a word to change its meaning. Many prefixes in the English language come from other languages, such as Latin or Greek. Examples include "pre-" which means "before" or "sub-" which means "under."

To determine which of the given options is a basic word part that comes from another language, let's break it down:

A. Affix: An affix is a word part that is attached to the beginning (prefix) or end (suffix) of a root word to change its meaning. While affixes may come from other languages, they are not considered basic word parts themselves.

B. Root: A root is a basic word part that carries the core meaning of the word and is usually of Greek or Latin origin. Root words are the foundation upon which many other words are built, making them an essential component of language.

C. Suffix: A suffix is a word part that is attached to the end of a root word to change its meaning or function. Like prefixes, suffixes can originate from other languages, but they are not considered basic word parts themselves.

D. Prefix: A prefix is a word part that is attached to the beginning of a root word to change its meaning. Similar to suffixes, prefixes may come from other languages, but they are not considered basic word parts themselves.

With this explanation in mind, the correct answer is B. Root, as it is a basic word part that often originates from other languages such as Greek or Latin.