The correct answer is the last option: If you take away the suffix –n and the prefix un-, the root word is “know”.
Prefixes and suffixes are sets of letters that are added at the beginning (prefix) or end of a word (suffix). They are not words by themselves, but they do change the words' meanings or categories.
In this case, the root is know. The suffix -n is used to change the word's category from verb (know) to noun (known). While, the prefix un- is used to mean NOT. As a result the meaning of the word UNKOWN would be not known or familiar.
An adjective phrase connects to a noun
An adverb phrase connects to a verb.
1. at soccer.
Adjective Phrase : at what?
soccer is a noun
So I THINK it's an adjective phrase.
The answer is C. because an autobiography is a biography about yourself.
C would be the most likely answer here.